Winter Sun 512x219

The weather on the refuge is similar to that of Fairbanks, Alaska, and is referred to as “continental subarctic,” characterized by great seasonal extremes of temperature and daylight. 

Temperature and precipitation

The Yukon Flats National Wildlife Refuge experiences extreme temperature variance and scarce precipitation. Fort Yukon holds the state record high temperature of 100° F (38° C), and comes close to the record low at –75° F (-59° C). Yukon Flats is the only place in the world where temperatures of 100° F have been recorded north of the Arctic Circle. The Refuge also experiences some of the coldest temperatures of any inhabited area. In the uplands and mountains surrounding the Yukon Flats, there is less temperature variance with cooler summers and warmer winters.



  • Annual total precipitation, 6.57 inches; ranging from 0.21 in April to 1.06 inches in August 
  • Annual snowfall, 41.9 inches; ranging from no snow in July and August to 6.8 inches in October 
  • Annual snow depth, 9 inches; ranging from no snow cover during the summer to 23 inches in March
  • Growing season is very short, averaging 81 days at Fort Yukon
    • Average date of last killing frost in spring - June 1
    • Average date of first killing frost in fall - August 21
    • Average freeze-up date of the Yukon River - October 28
  • Average break-up of Yukon River ice at Fort Yukon - May 15
    • Small lakes and ponds typically defrost a week before, while larger lakes are not free of ice for a week or more after the Yukon


See what the weather looks like today


In the summer, the Refuge experiences nearly continuous sunlight and twilight. Officially, the sun does not dip below the horizon between June 5 and July 7 in Fort Yukon; but daylight and twilight is continuous from May 13 through August 4.

In the winter, the sun stays below the horizon for a large part of the day, but twilight lasts for several hours. The shortest day of the year, December 21st, known as the winter solstice, is graced by the sun’s presence in Fort Yukon from 11:35 a.m. to 1:44 p.m., a period of 2 hours and 9 minutes of sunlight.