This report describes the typical weather at the Deadhorse Airport (Deadhorse, Alaska, United States) weather station over the course of an average year. It is based on the historical records from 1982 to 2012. Earlier records are either unavailable or unreliable.
Deadhorse, Alaska has a polar tundra climate. The area within 25 mi of this station is covered by tundra (71%), oceans and seas (25%), and lakes and rivers (4%).
Over the course of a year, the temperature typically varies from -24°F to 55°F and is rarely below -43°F or above 67°F.
The warm season lasts from June 8 to September 10 with an average daily high temperature above 41°F. The hottest day of the year is July 24, with an average high of 55°F and low of 41°F.
The cold season lasts from November 18 to April 6 with an average daily high temperature below 2°F. The coldest day of the year is January 25, with an average low of -24°F and high of -12°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 0:00 hours of daylight; the longest day is June 20 with 24:00 hours of daylight.
Due to its extreme latitude, Deadhorse, Alaska experiences polar day (also known as the midnight Sun) during summer and polar night during winter. 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 summer, the Sun is continuously above the horizon for 72 days, from May 15 to July 26.
In winter, the Sun is continuously below the horizon for 54 days, from November 24 to January 17.
Daylight saving time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.
The median cloud cover ranges from 67% (partly cloudy) to 100% (overcast). The sky is cloudiest on September 30 and clearest on March 15. The clearer part of the year begins around January 18. The cloudier part of the year begins around April 18.
On March 15, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 48% of the time, and overcast or mostly cloudy 50% of the time.
On September 30, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 89% of the time, and clear or mostly clear 9% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around October 7, occurring in 79% of days. Precipitation is least likely around February 25, occurring in 47% of days.
Over the entire year, the most common forms of precipitation are light snow and light rain.
Light snow is the most severe precipitation observed during 71% of those days with precipitation. It is most likely around October 22, when it is observed during 66% of all days.
Light rain is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around August 5, when it is observed during 30% of all days.
During the warm season, which lasts from June 8 to September 10, there is a 56% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (42% of days with precipitation have at worst light rain), light snow (33%), drizzle (12%), and moderate rain (8%).
During the cold season, which lasts from November 18 to April 6, there is a 54% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light snow (87% of days with precipitation have at worst light snow) and moderate snow (9%).
The likelihood of snow falling is highest around October 22, occurring in 74% of days. The season in which it is relatively likely for snow to fall spans from August 25 to June 22.
Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 65% (mildly humid) to 97% (very humid) over the course of the year, rarely dropping below 47% (comfortable) and reaching as high as 100% (very humid).
The air is driest around June 28, at which time the relative humidity drops below 73% (humid) three days out of four; it is most humid around August 23, exceeding 96% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a year, the dew point typically varies from -26°F (dry) to 46°F (dry) and is rarely below -40°F (dry) or above 54°F (very comfortable).
Over the course of the year typical wind speeds vary from 4 mph to 19 mph (light breeze to fresh breeze), rarely exceeding 30 mph (strong breeze).
The highest average wind speed of 14 mph (moderate breeze) occurs around October 1, at which time the average daily maximum wind speed is 19 mph (fresh breeze).
The lowest average wind speed of 11 mph (gentle breeze) occurs around September 3, at which time the average daily maximum wind speed is 16 mph (moderate breeze).