Winter Weather in Fort McPherson Northwest Territories, Canada

Daily high temperatures are around -2°F, rarely falling below -24°F or exceeding 23°F. The lowest daily average high temperature is -5°F on January 21.

Daily low temperatures are around -14°F, rarely falling below -34°F or exceeding 8°F. The lowest daily average low temperature is -17°F on January 22.

For reference, on July 5, the hottest day of the year, temperatures in Fort McPherson typically range from 54°F to 73°F, while on January 20, the coldest day of the year, they range from -17°F to -5°F.

The figure below shows you a compact characterization of the hourly average winter temperatures. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Pangody, Russia (3,120 miles away) is the far-away foreign place with temperatures most similar to Fort McPherson (view comparison).

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The winter in Fort McPherson experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 68% to 63%.

The clearest day of the winter is February 24, with clear, mostly clear, or partly cloudy conditions 37% of the time.

For reference, on April 6, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 75%, while on June 24, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 48%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Fort McPherson, the chance of a wet day over the course of the winter is gradually decreasing, starting the season at 6% and ending it at 3%.

For reference, the year's highest daily chance of a wet day is 21% on July 18, and its lowest chance is 3% on March 9.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day snowfall during the winter in Fort McPherson is gradually decreasing, starting the season at 2.5 inches, when it rarely exceeds 6.0 inches or falls below 0.1 inches, and ending the season at 1.5 inches, when it rarely exceeds 3.6 inches or falls below -0.0 inches.

Due to its extreme latitude, Fort McPherson experiences polar day (also known as the midnight Sun) during the summer and polar night during the winter. These are periods of time in which the sun is continuously above or below the horizon for more than one day. The precise start and end dates of polar day and night vary from year to year and depend on the precise location and elevation of the observer, and the local topography.

In the winter in Fort McPherson during 2025, the Sun is continuously below the horizon for 1.1 weeks, setting at 1:59 PM on December 17, and not rising again until 1:52 PM on December 25. As such, polar night begins and ends during the winter.

The longest day of the winter is February 28, with 9 hours, 46 minutes of daylight.

The latest sunrise of the winter in Fort McPherson is 1:52 PM on December 17 and the earliest sunrise is 4 hours, 33 minutes earlier at 9:19 AM on February 28.

The earliest sunset is 1:59 PM on December 17 and the latest sunset is 5 hours, 7 minutes later at 7:05 PM on February 28.

Daylight saving time is observed in Fort McPherson during 2025, but it neither starts nor ends during the winter, so the entire season is in standard time.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

The figure below presents a compact representation of key lunar data for the winter of 2025. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in Fort McPherson is essentially constant during the winter, remaining around 0% throughout.

For reference, on June 21, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Fort McPherson is essentially constant during the winter, remaining within 0.4 miles per hour of 7.6 miles per hour throughout.

For reference, on June 3, the windiest day of the year, the daily average wind speed is 8.2 miles per hour, while on October 18, the calmest day of the year, the daily average wind speed is 7.2 miles per hour.

The highest daily average wind speed during the winter is 8.0 miles per hour on January 6.

The hourly average wind direction in Fort McPherson throughout the winter is predominantly from the north, with a peak proportion of 48% on December 1.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Fort McPherson typically lasts for 3.4 months (105 days), from around May 27 to around September 9, rarely starting before May 11 or after June 11, and rarely ending before August 19 or after September 29.

The winter in Fort McPherson is reliably fully outside of the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Fort McPherson are very rapidly decreasing during the winter, decreasing by 1,004°F, from 1,004°F to 0°F, over the course of the season.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in Fort McPherson is gradually increasing during the winter, rising by 1.0 kWh, from 0.0 kWh to 1.0 kWh, over the course of the season.

The lowest average daily incident shortwave solar energy during the winter is 0.0 kWh on December 22.

For the purposes of this report, the geographical coordinates of Fort McPherson are 67.439 deg latitude, -134.885 deg longitude, and 69 ft elevation.

The topography within 2 miles of Fort McPherson contains only modest variations in elevation, with a maximum elevation change of 108 feet and an average elevation above sea level of 41 feet. Within 10 miles contains only modest variations in elevation (1,316 feet). Within 50 miles contains very significant variations in elevation (5,499 feet).

The area within 2 miles of Fort McPherson is covered by trees (66%) and water (10%), within 10 miles by trees (56%) and shrubs (29%), and within 50 miles by trees (35%) and shrubs (27%).