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Saint Lawrence Freeze Up Date Outlook
National Weather Service Buffalo NY
335 AM EST Sat Nov 15 2025

...FREEZE-UP DATE OUTLOOK FOR THE SAINT LAWRENCE RIVER...

The date of the first freeze-up on the Saint Lawrence River near
Massena, NY is forecast to be December 30, 2025.

WATER TEMPERATURES...

Water temperatures have been running above average across the
eastern basin of Lake Ontario and the Saint Lawrence River through
the fall. The warm lake and river temperatures were driven by long
stretches of above average temperatures and very dry weather from
September through the first three weeks of October. Cooler weather
during the first half of November has removed some of the excess
warmth, but water temperatures are still a few degrees above
average.

Water Temperatures November 15th:

Alexandria Bay, NY   50F (normal 48F)

LAKE ONTARIO OUTFLOW...

The outflow from Lake Ontario has averaged around 229,000 CFS
through the first half of November, which is slightly below the long
term average for this time of year. Outflow from Lake Ontario into
the Saint Lawrence River is expected to be near to slightly below
average through the rest of November. Below average outflow can
reduce the speed of the current in the river and allow ice to more
readily form.

AIR TEMPERATURES...

Temperatures were warm much of the time from September through the
first three weeks of October, with numerous stretches of very warm
days. Much cooler weather has prevailed through the first half of
November, with the majority of days seeing below average
temperatures.

November Average Air Temperatures through November 14th:

Watertown, NY   37.0F (4.2F below normal)
Massena, NY     34.9F (4.1F below normal)

FORECAST FOR THE REST OF NOVEMBER...

Below average temperatures through early next week will give way to
a warming trend later next week through late November. The latest 8
to 14 day outlook continues to support a high likelihood of above
average temperatures for the week spanning November 22 through 28.
Following this warmer pattern, early indications support increasing
chances of a colder pattern and below average temperatures across
the Great Lakes and Saint Lawrence Valley in early December.

A weak La Nina pattern has developed in the equatorial Pacific
Ocean, and is favored to continue through the first half of winter
before weakening by late winter or early spring. Weak or neutral
conditions in the Pacific Ocean can allow for other, more difficult
to predict circulation patterns to have greater influence on the
weather in the Great Lakes. The long term outlook shows equal
chances for above, below, or near average temperatures through the
winter in the lower Great Lakes and Saint Lawrence Valley.

Given the above factors, and the overall trend in later onset of ice
cover over the past 15 years, the first freeze-up on the Saint
Lawrence River near Massena, NY is forecast to be December 30, 2025.
This date is around a week later than the long term average.

NOTE: Once the water temperature drops to the mid 30s, ice cover can
develop in just one very cold, calm night.

NOTE: This forecast is for the first shore to shore freeze-up of the
Saint Lawrence River near Massena, NY. The first permanent shore to
shore ice often occurs several weeks later.

$$

Hitchcock