Climate of Alaska

Köppen climate types in SE Alaska

The climate in Juneau and the southeast panhandle is a mid-latitude oceanic climate (Köppen climate classification Cfb) in the southern sections and an oceanic, marine subpolar climate (similar to Scotland, or Haida Gwaii), (Köppen Cfc) in the northern parts. Much of the southern parts are temperate rainforest. On an annual basis, southern portions are both the wettest and warmest part of Alaska, with milder temperatures in the winter and high precipitation throughout the year. Average monthly precipitation is generally highest in the autumn months, especially October, and lowest in May or June. This is also the only region in Alaska in which the average daytime high temperature is above freezing during the winter months, except for in the southern parts of the Aleutian islands such as Unalaska.

The climate in south central Alaska, with Anchorage as a typical city, is mild by Alaskan standards. This is due in large part to its proximity to the coast. While it does not get nearly as much rain as the southeast of Alaska, it does get more snow, although days tend to be clearer here. It is a subarctic climate (Köppen Dfc) due to its short, cool summers. There are frequent, strong southeast winds known as the Knik wind in the vicinity of Palmer, especially in the winter months.[1]

The climate of Western Alaska is determined largely by the Bering Sea and the Gulf of Alaska. It is a subarctic oceanic climate in the southwest and a continental subarctic climate farther north. The temperature is somewhat moderate considering how far north the area is. This area has a tremendous amount of variety, especially when considering precipitation. The northern side of the Seward Peninsula is technically a desert with less than 10 inches (254 mm) of precipitation annually, while some locations between Dillingham and Bethel average around 100 inches (2,540 mm) of precipitation.[2]

The climate of the interior of Alaska is best described as extreme and is an excellent example of a true continental subarctic climate. Some of the hottest and coldest temperatures in Alaska occur around the area near Fairbanks. The summers can have temperatures reaching into the 90s °F (near 34 °C), while in the winter, the temperature can fall below −50 °F (−45.6 °C), and in rare cases, below −60 °F (−51.1 °C). Precipitation is generally sparse around the year, peaking during the summer months, and virtually all precipitation between October and April falls as snow. Ice fog is a significant hazard during especially cold periods between November and March.[3]

The climate in the extreme north of Alaska is what would be expected for an area north of the Arctic Circle. It is an Arctic climate (Köppen ET) with long, very cold winters and short, cool summers. The sun does not rise at all during some weeks in the winter, and is out for 24 hours during some weeks in the summer. However, despite 24 hours of sunshine in the summertime, the average low temperature is barely above freezing in Utqiagvik in July, at 34 °F (1.1 °C) and snow may fall any month of the year.[4] North Alaska is the coldest region in Alaska.[3]

The highest and lowest recorded temperatures in Alaska are both in the Interior. The highest is 100 °F (37.8 °C) in Fort Yukon on June 27, 1915.[5][6][7][8] The lowest Alaska temperature is −80 °F (−62.2 °C) in Prospect Creek on January 23, 1971,[5][6] 1 °F (0.6 °C) above the lowest temperature recorded in continental North America (in Snag, Yukon, Canada).[9] Alaska also holds the extreme US record low temperatures for every month except September and October.