The Alaska Current brings relatively warm water and moist air north to the rugged southeast coast of Alaska. This results in a humid maritime climate characterized by relatively heavy precipitation with a small temperature range between seasons.
Well prepared visitors will have rain gear and layered clothing at any time of year! Average annual precipitation at the Sitka Airport averages about 90 inches with most precipitation occurring as rain.
Winters at sea level are warmer than would be expected at such northern latitudes. Winter temperatures range from the high teens to the 40s Fahrenheit; the average daily low in January is 31º Fahrenheit.
Summers remain cool. Summer temperatures range from high 50s to high 60s Fahrenheit; the average daily high in July and August is 55º Fahrenheit.In early and mid-summer a high pressure ridge tends to move north through southeast Alaska creating a relatively dry season. In mid-summer high pressure tends to move back into the central Pacific, permitting storms to move into the Gulf of Alaska with stronger and more frequent frontal systems passing over southeast Alaska.
The wettest months of the year are September through November, with October receiving an average of 14.8 inches. (A Sitka November record of 19.67 inches was set in 2004.)