Routine Fire Wx Fcst (With/Without 6-10 Day Outlook)
Issued by NWS Billings, MT
Issued by NWS Billings, MT
435 FNUS55 KBYZ 182006 FWFBYZ Fire Weather Planning Forecast for SCen and SErn Montana National Weather Service Billings MT 206 PM MDT Fri Sep 18 2026 .DISCUSSION... A slow-moving weather system will bring frequent showers and rounds of embedded thunderstorms over south central Montana and rounds of showers and thunderstorms over northern Wyoming into south east Montana through this weekend. Precipitation with this system will be widespread and significant, with much of the region seeing between 1 and 3 inches of total rainfall and 4+ inches possible where thunderstorms are more persistent. Snow levels will remain high, above 10k feet. After the cool weekend conditions trend warm and dry. Archer MTZ123-191030- Gallatin National Forest- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Rain showers and scattered thunderstorms in the evening, then numerous rain showers and isolated thunderstorms overnight. * Min temperature.......45-52 at 5000 feet...39-49 at 7000 feet. * 24 hr trend.........4 degrees cooler. * Max humidity..........93-98 percent. * 24 hr trend.........27 percent wetter. * Wind (20 ft) * Slope/valley.........Light winds. * Ridgetop.............Southeast 5 to 10 mph. * Chance of lightning...35 percent. * CWR...................70 percent. .SATURDAY... * Sky/weather...........Cloudy. Areas of fog in the morning. Rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. * Max temperature.......53-63 at 5000 feet...45-55 at 7000 feet. * 24 hr trend.........12 degrees cooler. * Min humidity..........73-83 percent at 5000 feet...78-88 percent at 7000 feet. * 24 hr trend.........28 percent wetter. * Wind (20 ft) * Slope/valley.........Light winds in the morning becoming north 5 to 10 mph in the afternoon. * Ridgetop.............Light winds. * Chance of lightning...36 percent. * CWR...................90 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then scattered rain showers overnight. * Min temperature.......41-50 at 5000 feet...37-47 at 7000 feet. * 24 hr trend.........3 degrees cooler. * Max humidity..........88-98 percent at 5000 feet...84-94 percent at 7000 feet. * 24 hr trend.........4 percent drier. * Wind (20 ft) * Slope/valley.........Light winds. * Ridgetop.............Light winds. * Chance of lightning...16 percent. * CWR...................40 percent. .SUNDAY... * Sky/weather...........Mostly cloudy. Scattered rain showers in the morning. * Max temperature.......60-70 at 5000 feet...49-59 at 7000 feet. * 24 hr trend.........8 degrees warmer. * Min humidity..........50-60 percent at 5000 feet...55-65 percent at 7000 feet. * 24 hr trend.........34 percent drier. * Wind (20 ft) * Slope/valley.........Light winds in the morning becoming northwest 5 to 10 mph in the afternoon. * Ridgetop.............Northwest 5 to 10 mph. * Chance of lightning...13 percent. * CWR...................Less than 10 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly clear. Lows 40 to 48. South winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 42 to 51. Highs 68 to 78. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 44 to 54. Highs 70 to 80. South winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 44 to 54. Highs 70 to 80. Southwest winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 45 to 55. Highs 72 to 82. .FRIDAY...Mostly sunny. Highs 72 to 82. $$ MTZ124-191030- Wheatland County/Sweet Grass County- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then rain showers and isolated thunderstorms overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......50-55. * 24 hr trend.........1 degree warmer. * Max humidity..........93-98 percent. * 24 hr trend.........15 percent wetter. * Wind (20 ft) * Plains...............Northwest winds 5 to 15 mph. * Chance of lightning...35 percent. * CWR...................100 percent. .SATURDAY... * Sky/weather...........Cloudy with rain showers and isolated thunderstorms. Some thunderstorms may produce heavy rainfall. * Max temperature.......56-61. * 24 hr trend.........17 degrees cooler. * Min humidity..........80-85 percent. * 24 hr trend.........42 percent wetter. * Wind (20 ft) * Plains...............North winds 5 to 15 mph. * Chance of lightning...24 percent. * CWR...................100 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers in the evening, then numerous rain showers overnight. * Min temperature.......45-50. * 24 hr trend.........5 degrees cooler. * Max humidity..........92-97 percent. * 24 hr trend.........1 percent drier. * Wind (20 ft) * Plains...............Northwest winds 5 to 15 mph. * Chance of lightning...11 percent. * CWR...................80 percent. .SUNDAY... * Sky/weather...........Cloudy with scattered rain showers in the morning, then partly sunny with isolated showers and thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......63-68. * 24 hr trend.........7 degrees warmer. * Min humidity..........54-59 percent. * 24 hr trend.........26 percent drier. * Wind (20 ft) * Plains...............North winds 5 to 10 mph. * Chance of lightning...15 percent. * CWR...................20 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Lows 44 to 49. Southeast winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 45 to 50. Highs 71 to 76. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 47 to 52. Highs 75 to 80. Southwest winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 46 to 51. Highs 75 to 80. West winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 47 to 52. Highs 75 to 80. .FRIDAY...Mostly sunny. Highs 76 to 81. $$ MTZ125-191030- Stillwater County- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then rain showers and isolated thunderstorms overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......50-55. * 24 hr trend.........Unchanged. * Max humidity..........100 percent. * 24 hr trend.........20 percent wetter. * Wind (20 ft) * Plains...............West winds 5 to 10 mph in the evening becoming light overnight. * Chance of lightning...36 percent. * CWR...................100 percent. .SATURDAY... * Sky/weather...........Cloudy. Patchy fog in the morning. Rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......56-61. * 24 hr trend.........17 degrees cooler. * Min humidity..........83-88 percent. * 24 hr trend.........43 percent wetter. * Wind (20 ft) * Plains...............Northwest winds 5 to 10 mph. * Chance of lightning...34 percent. * CWR...................100 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......47-52. * 24 hr trend.........3 degrees cooler. * Max humidity..........86-91 percent. * 24 hr trend.........12 percent drier. * Wind (20 ft) * Plains...............Northwest winds 5 to 10 mph. * Chance of lightning...17 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy. Numerous rain showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. * Max temperature.......61-66. * 24 hr trend.........5 degrees warmer. * Min humidity..........60-65 percent. * 24 hr trend.........23 percent drier. * Wind (20 ft) * Plains...............Northwest winds 5 to 10 mph. * Chance of lightning...14 percent. * CWR...................40 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Lows 43 to 48. South winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 46 to 51. Highs 70 to 75. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 48 to 53. Highs 74 to 79. South winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 48 to 53. Highs 75 to 80. Southwest winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 49 to 54. Highs 76 to 81. .FRIDAY...Mostly sunny. Highs 77 to 82. $$ MTZ126-191030- Beartooth Ranger District Custer National Forest- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......50-57 at 5000 feet...42-52 at 7000 feet. * 24 hr trend.........5 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........44 percent wetter. * Wind (20 ft) * Slope/valley.........West winds 5 to 10 mph. * Ridgetop.............East 5 to 10 mph. * Chance of lightning...32 percent. * CWR...................90 percent. .SATURDAY... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......54-62 at 5000 feet...46-56 at 7000 feet. * 24 hr trend.........14 degrees cooler. * Min humidity..........84-94 percent at 5000 feet...82-92 percent at 7000 feet. * 24 hr trend.........41 percent wetter. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 15 mph. * Ridgetop.............Northeast 5 to 10 mph. * Chance of lightning...36 percent. * CWR...................90 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then numerous rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......47-52 at 5000 feet...38-48 at 7000 feet. * 24 hr trend.........2 degrees cooler. * Max humidity..........88-93 percent. * 24 hr trend.........10 percent drier. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 15 mph. * Ridgetop.............Northwest 5 to 15 mph. * Chance of lightning...18 percent. * CWR...................80 percent. .SUNDAY... * Sky/weather...........Cloudy with numerous showers and isolated thunderstorms. * Max temperature.......55-62 at 5000 feet...48-58 at 7000 feet. * 24 hr trend.........3 degrees warmer. * Min humidity..........69-79 percent at 5000 feet...73-83 percent at 7000 feet. * 24 hr trend.........10 percent drier. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 10 mph. * Ridgetop.............Northwest 5 to 10 mph. * Chance of lightning...14 percent. * CWR...................60 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Isolated showers. Lows 44 to 52. West winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 47 to 55. Highs 62 to 71. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 50 to 57. Highs 68 to 77. South winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Isolated showers. Lows 50 to 58. Highs 69 to 77. Southwest winds 5 to 15 mph. .THURSDAY...Partly cloudy. Lows 50 to 59. Highs 70 to 79. .FRIDAY...Mostly sunny. Highs 71 to 79. $$ MTZ127-191030- Golden Valley County/Musselshell county- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy. Numerous rain showers and scattered thunderstorms in the evening, then rain showers and scattered thunderstorms overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......51-56. * 24 hr trend.........3 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........50 percent wetter. * Wind (20 ft) * Plains...............North winds 5 to 15 mph. * Chance of lightning...32 percent. * CWR...................100 percent. .SATURDAY... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Some thunderstorms may produce heavy rainfall. * Max temperature.......53-58. * 24 hr trend.........19 degrees cooler. * Min humidity..........89-94 percent. * 24 hr trend.........48 percent wetter. * Wind (20 ft) * Plains...............North winds 10 to 20 mph. * Chance of lightning...33 percent. * CWR...................100 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......49-54. * 24 hr trend.........2 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............North winds 10 to 20 mph. * Chance of lightning...23 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy. Rain showers in the morning, then numerous rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......56-61. * 24 hr trend.........3 degrees warmer. * Min humidity..........89-94 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............North winds 5 to 15 mph. * Chance of lightning...15 percent. * CWR...................80 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Lows 48 to 53. East winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 49 to 54. Highs 65 to 70. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 52 to 57. Highs 72 to 77. South winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 52 to 57. Highs 72 to 77. Southwest winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 53 to 58. Highs 73 to 78. .FRIDAY...Mostly sunny. Highs 74 to 79. $$ MTZ128-191030- Yellowstone County- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Some thunderstorms may produce heavy rainfall. * Min temperature.......54-59. * 24 hr trend.........1 degree warmer. * Max humidity..........100 percent. * 24 hr trend.........33 percent wetter. * Wind (20 ft) * Plains...............North winds 5 to 15 mph. * Chance of lightning...37 percent. * CWR...................100 percent. .SATURDAY... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Some thunderstorms may produce heavy rainfall. * Max temperature.......59-64. * 24 hr trend.........19 degrees cooler. * Min humidity..........88-93 percent. * 24 hr trend.........51 percent wetter. * Wind (20 ft) * Plains...............North winds 5 to 15 mph. * Chance of lightning...36 percent. * CWR...................100 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......51-56. * 24 hr trend.........3 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............North winds 10 to 20 mph. * Chance of lightning...25 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy. Rain showers in the morning, then scattered rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......61-66. * 24 hr trend.........2 degrees warmer. * Min humidity..........81-86 percent. * 24 hr trend.........7 percent drier. * Wind (20 ft) * Plains...............Northwest winds 5 to 15 mph. * Chance of lightning...17 percent. * CWR...................70 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Lows 48 to 53. Northeast winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 48 to 53. Highs 70 to 75. South winds 5 to 10 mph. .TUESDAY...Partly cloudy. Lows 51 to 56. Highs 76 to 81. Southwest winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 51 to 56. Highs 76 to 81. Southwest winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 51 to 56. Highs 77 to 82. .FRIDAY...Mostly sunny. Highs 78 to 83. $$ MTZ129-191030- Crow Indian Reservation/Bighorn Canyon Rec Area- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Some thunderstorms may produce heavy rainfall. * Min temperature.......48-57 at 5000 feet...47-52 at 7000 feet. * 24 hr trend.........2 degrees cooler. * Max humidity..........88-98 percent at 5000 feet...100 percent at 7000 feet. * 24 hr trend.........7 percent wetter. * Wind (20 ft) * Slope/valley.........South winds 5 to 10 mph in the evening shifting to the north overnight. * Ridgetop.............East 5 to 15 mph. * Chance of lightning...38 percent. * CWR...................90 percent. .SATURDAY... * Sky/weather...........Mostly cloudy. Patchy fog in the morning. Rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......54-64 at 5000 feet...49-55 at 7000 feet. * 24 hr trend.........16 degrees cooler. * Min humidity..........80-90 percent at 5000 feet...87-97 percent at 7000 feet. * 24 hr trend.........62 percent wetter. * Wind (20 ft) * Slope/valley.........North winds 5 to 10 mph. * Ridgetop.............East 5 to 10 mph. * Chance of lightning...40 percent. * CWR...................90 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then numerous rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......45-52 at 5000 feet...43-48 at 7000 feet. * 24 hr trend.........5 degrees cooler. * Max humidity..........87-97 percent at 5000 feet...93-100 percent at 7000 feet. * 24 hr trend.........Unchanged. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 15 mph. * Ridgetop.............West 5 to 10 mph. * Chance of lightning...28 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy. Numerous rain showers in the morning, then numerous rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......53-63 at 5000 feet...47-53 at 7000 feet. * 24 hr trend.........3 degrees cooler. * Min humidity..........75-85 percent at 5000 feet...82-92 percent at 7000 feet. * 24 hr trend.........3 percent drier. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 15 mph. * Ridgetop.............Southwest 5 to 10 mph. * Chance of lightning...20 percent. * CWR...................70 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Scattered showers. Lows 46 to 51. Southwest winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 48 to 55. Highs 63 to 73. Southeast winds 5 to 10 mph. .TUESDAY...Mostly clear. Lows 52 to 57. Highs 68 to 78. Southeast winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 52 to 57. Highs 69 to 79. Southeast winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 53 to 58. Highs 70 to 80. .FRIDAY...Mostly sunny. Highs 71 to 81. $$ MTZ130-191030- Northern Rosebud/Northern Treasure Counties- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Scattered showers and thunderstorms in the evening, then rain showers and scattered thunderstorms overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......55-60. * 24 hr trend.........4 degrees warmer. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............Northeast winds 5 to 10 mph. * Chance of lightning...30 percent. * CWR...................70 percent. .SATURDAY... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Some thunderstorms may produce heavy rainfall. * Max temperature.......61-66. * 24 hr trend.........18 degrees cooler. * Min humidity..........95-100 percent. * 24 hr trend.........59 percent wetter. * Wind (20 ft) * Plains...............Northeast winds 5 to 15 mph. * Chance of lightning...27 percent. * CWR...................100 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......51-56. * 24 hr trend.........4 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............East winds 5 to 15 mph. * Chance of lightning...20 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy. Rain showers in the morning, then rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......61-66. * 24 hr trend.........Unchanged. * Min humidity..........88-93 percent. * 24 hr trend.........7 percent drier. * Wind (20 ft) * Plains...............East winds 5 to 15 mph. * Chance of lightning...17 percent. * CWR...................70 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Scattered showers. Lows 48 to 53. East winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 48 to 53. Highs 70 to 75. Southeast winds 5 to 15 mph. .TUESDAY...Mostly clear. Lows 50 to 55. Highs 76 to 81. Southeast winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 50 to 55. Highs 77 to 82. Light winds. .THURSDAY...Mostly clear. Lows 51 to 56. Highs 79 to 84. .FRIDAY...Mostly sunny. Highs 80 to 85. $$ MTZ131-191030- Northern Cheyenne Indian Reservation/Ashland Ranger District Custer Natl Forest- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Cloudy with rain showers and scattered thunderstorms. Patchy fog overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......53-58. * 24 hr trend.........4 degrees warmer. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 10 mph. * Ridgetop.............Southeast 5 to 10 mph. * Chance of lightning...39 percent. * CWR...................70 percent. .SATURDAY... * Sky/weather...........Mostly cloudy. Patchy fog in the morning. Rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......64-69. * 24 hr trend.........17 degrees cooler. * Min humidity..........82-87 percent. * 24 hr trend.........52 percent wetter. * Wind (20 ft) * Slope/valley.........North winds 5 to 10 mph. * Ridgetop.............Southeast 5 to 10 mph. * Chance of lightning...36 percent. * CWR...................80 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then numerous rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......49-54. * 24 hr trend.........4 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Slope/valley.........East winds 5 to 10 mph. * Ridgetop.............Southwest 5 to 10 mph. * Chance of lightning...28 percent. * CWR...................100 percent. .SUNDAY... * Sky/weather...........Cloudy. Rain showers in the morning, then rain showers and isolated thunderstorms in the afternoon. * Max temperature.......60-65. * 24 hr trend.........4 degrees cooler. * Min humidity..........75-80 percent. * 24 hr trend.........7 percent drier. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 15 mph. * Ridgetop.............Light winds. * Chance of lightning...17 percent. * CWR...................60 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Scattered showers. Lows 45 to 50. East winds 5 to 10 mph. .MONDAY...Mostly clear. Lows 46 to 51. Highs 69 to 74. Southeast winds 5 to 10 mph. .TUESDAY...Mostly clear. Lows 49 to 54. Highs 77 to 82. Southeast winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 49 to 54. Highs 78 to 83. Southeast winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 51 to 56. Highs 80 to 85. .FRIDAY...Mostly sunny. Highs 80 to 85. $$ MTZ132-191030- Custer County- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Scattered rain showers and isolated thunderstorms in the evening, then scattered showers and thunderstorms overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......55-60. * 24 hr trend.........Unchanged. * Max humidity..........100 percent. * 24 hr trend.........4 percent wetter. * Wind (20 ft) * Plains...............East winds 5 to 10 mph. * Chance of lightning...29 percent. * CWR...................40 percent. .SATURDAY... * Sky/weather...........Cloudy with rain showers and isolated thunderstorms. Some thunderstorms may produce heavy rainfall. * Max temperature.......61-66. * 24 hr trend.........17 degrees cooler. * Min humidity..........83-88 percent. * 24 hr trend.........41 percent wetter. * Wind (20 ft) * Plains...............East winds 5 to 15 mph. * Chance of lightning...18 percent. * CWR...................90 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......51-56. * 24 hr trend.........4 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............East winds 10 to 20 mph. * Chance of lightning...16 percent. * CWR...................80 percent. .SUNDAY... * Sky/weather...........Cloudy with rain showers. * Max temperature.......58-63. * 24 hr trend.........3 degrees cooler. * Min humidity..........82-87 percent. * 24 hr trend.........1 percent drier. * Wind (20 ft) * Plains...............East winds 10 to 20 mph. * Chance of lightning...12 percent. * CWR...................90 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Isolated showers. Lows 48 to 53. Southeast winds 5 to 15 mph. .MONDAY...Partly cloudy. Lows 49 to 54. Highs 65 to 70. Southeast winds 5 to 15 mph. .TUESDAY...Mostly clear. Lows 52 to 57. Highs 73 to 78. Southeast winds 5 to 15 mph. .WEDNESDAY...Mostly clear. Lows 53 to 58. Highs 76 to 81. Southeast winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 54 to 59. Highs 77 to 82. .FRIDAY...Mostly sunny. Highs 78 to 83. $$ MTZ133-191030- Sioux Ranger District Custer National Forest- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Scattered rain showers and isolated thunderstorms overnight. * Min temperature.......54-59. * 24 hr trend.........2 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............Southeast winds 5 to 15 mph. * Chance of lightning...15 percent. * CWR...................20 percent. .SATURDAY... * Sky/weather...........Cloudy. Numerous rain showers in the morning, then rain showers and isolated thunderstorms in the afternoon. * Max temperature.......62-67. * 24 hr trend.........12 degrees cooler. * Min humidity..........80-85 percent. * 24 hr trend.........23 percent wetter. * Wind (20 ft) * Plains...............East winds 10 to 20 mph. Gusts up to 30 mph in the afternoon. * Chance of lightning...17 percent. * CWR...................60 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and isolated thunderstorms in the evening, then rain showers overnight. * Min temperature.......50-55. * 24 hr trend.........4 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Plains...............East winds 10 to 20 mph. * Chance of lightning...15 percent. * CWR...................90 percent. .SUNDAY... * Sky/weather...........Cloudy with rain showers. * Max temperature.......58-63. * 24 hr trend.........4 degrees cooler. * Min humidity..........88-93 percent. * 24 hr trend.........8 percent wetter. * Wind (20 ft) * Plains...............Southeast winds 10 to 20 mph. Gusts up to 30 mph in the afternoon. * Chance of lightning...12 percent. * CWR...................90 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Cloudy. Numerous showers. Lows 48 to 53. Southeast winds 10 to 20 mph. .MONDAY...Mostly cloudy. Lows 48 to 53. Highs 63 to 68. Southeast winds 10 to 20 mph with gusts to around 30 mph. .TUESDAY...Partly cloudy. Lows 51 to 56. Highs 71 to 76. Southeast winds 5 to 15 mph with gusts to around 30 mph. .WEDNESDAY...Mostly clear. Isolated showers. Lows 51 to 56. Highs 76 to 81. Southeast winds 5 to 10 mph. .THURSDAY...Mostly clear. Lows 52 to 57. Highs 78 to 83. .FRIDAY...Mostly sunny. Highs 78 to 83. $$ WYZ274-191030- Sheridan County- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Rain showers and scattered thunderstorms in the evening, then scattered rain showers and isolated thunderstorms overnight. Patchy fog overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......49-54. * 24 hr trend.........1 degree warmer. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Slope/valley.........Southwest winds 5 to 10 mph in the evening becoming light overnight. * Ridgetop.............South 5 to 10 mph. * Chance of lightning...38 percent. * CWR...................70 percent. .SATURDAY... * Sky/weather...........Mostly cloudy. Patchy fog in the morning. Numerous rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......63-68. * 24 hr trend.........15 degrees cooler. * Min humidity..........82-87 percent. * 24 hr trend.........46 percent wetter. * Wind (20 ft) * Slope/valley.........Light winds in the morning becoming northwest 5 to 10 mph in the afternoon. * Ridgetop.............West 5 to 10 mph. * Chance of lightning...36 percent. * CWR...................90 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Rain showers and scattered thunderstorms in the evening, then numerous rain showers overnight. Patchy fog overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......45-50. * 24 hr trend.........4 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 10 mph. * Ridgetop.............Southwest 5 to 10 mph. * Chance of lightning...29 percent. * CWR...................80 percent. .SUNDAY... * Sky/weather...........Cloudy. Patchy fog in the morning. Numerous rain showers in the morning, then rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......61-66. * 24 hr trend.........2 degrees cooler. * Min humidity..........73-78 percent. * 24 hr trend.........9 percent drier. * Wind (20 ft) * Slope/valley.........Northwest winds 5 to 10 mph. * Ridgetop.............Light winds. * Chance of lightning...22 percent. * CWR...................70 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Scattered showers and isolated thunderstorms. Lows 41 to 46. Northwest winds 5 to 10 mph. .MONDAY...Mostly clear. Isolated showers. Lows 40 to 45. Highs 69 to 74. Light winds. .TUESDAY...Mostly clear. Lows 45 to 50. Highs 76 to 81. Southeast winds 5 to 10 mph. .WEDNESDAY...Mostly clear. Lows 44 to 49. Highs 77 to 82. Light winds. .THURSDAY...Mostly clear. Lows 45 to 50. Highs 79 to 84. .FRIDAY...Mostly sunny. Highs 80 to 85. $$ WYZ284-191030- Bighorn National Forest- 206 PM MDT Fri Sep 18 2026 .Tonight... * Sky/weather...........Mostly cloudy. Rain showers and scattered thunderstorms in the evening, then numerous rain showers and isolated thunderstorms overnight. Patchy fog through the night. Some thunderstorms may produce heavy rainfall. * Min temperature.......39-44. * 24 hr trend.........1 degree cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * At Burgess Jct.......South winds 5 to 10 mph. * Chance of lightning...38 percent. * CWR...................60 percent. .SATURDAY... * Sky/weather...........Mostly cloudy. Patchy fog in the morning. Numerous rain showers and isolated thunderstorms in the morning, then rain showers and scattered thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......51-56. * 24 hr trend.........12 degrees cooler. * Min humidity..........80-85 percent. * 24 hr trend.........38 percent wetter. * Wind (20 ft) * At Burgess Jct.......Northwest winds 5 to 10 mph. * Chance of lightning...38 percent. * CWR...................80 percent. .SATURDAY NIGHT... * Sky/weather...........Cloudy. Numerous rain showers and isolated thunderstorms in the evening, then numerous rain showers overnight. Some thunderstorms may produce heavy rainfall. * Min temperature.......34-39. * 24 hr trend.........5 degrees cooler. * Max humidity..........100 percent. * 24 hr trend.........Unchanged. * Wind (20 ft) * At Burgess Jct.......West winds 5 to 10 mph. * Chance of lightning...24 percent. * CWR...................50 percent. .SUNDAY... * Sky/weather...........Cloudy. Numerous rain showers in the morning, then rain showers and isolated thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall. * Max temperature.......47-52. * 24 hr trend.........4 degrees cooler. * Min humidity..........76-81 percent. * 24 hr trend.........4 percent drier. * Wind (20 ft) * At Burgess Jct.......Northwest winds 5 to 15 mph. * Chance of lightning...23 percent. * CWR...................90 percent. .Forecast days 3 through 7...... .SUNDAY NIGHT...Mostly cloudy. Scattered showers. Lows 32 to 37. West winds 5 to 10 mph. .MONDAY...Mostly clear. Isolated showers. Lows 35 to 40. Highs 55 to 60. Southwest winds 5 to 10 mph. .TUESDAY...Partly cloudy. Isolated showers. Lows 39 to 44. Highs 61 to 66. Southwest winds 5 to 10 mph. .WEDNESDAY...Partly cloudy. Scattered showers. Lows 39 to 44. Highs 62 to 67. Southwest winds 5 to 15 mph. .THURSDAY...Mostly clear. Lows 40 to 45. Highs 64 to 69. .FRIDAY...Mostly sunny. Highs 65 to 70. $$ weather.gov/billings