Average Weather at Adak Airport Alaska, United States
At Adak Airport, the summers are short, cold, and windy; the winters are long, chilly, and extremely windy; and it is overcast year round. Over the course of the year, the temperature typically varies from 29°F to 56°F and is rarely below 20°F or above 61°F.
The warm season lasts for 2.5 months, from July 5 to September 20, with an average daily high temperature above 52°F. The hottest day of the year is August 13, with an average high of 56°F and low of 47°F.
The cold season lasts for 4.2 months, from November 28 to April 5, with an average daily high temperature below 40°F. The coldest day of the year is January 24, with an average low of 29°F and high of 35°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
At Adak Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year at Adak Airport begins around September 1 and lasts for 3.4 months, ending around December 14. On October 14, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 41% of the time, and overcast or mostly cloudy 59% of the time.
The cloudier part of the year begins around December 14 and lasts for 8.6 months, ending around September 1. On July 6, the cloudiest day of the year, the sky is overcast or mostly cloudy 87% of the time, and clear, mostly clear, or partly cloudy 13% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Adak Airport varies throughout the year.
The wetter season lasts 8.6 months, from July 9 to March 27, with a greater than 30% chance of a given day being a wet day. The chance of a wet day peaks at 40% on November 12.
The drier season lasts 3.4 months, from March 27 to July 9. The smallest chance of a wet day is 20% on May 5.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 38% on November 9.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Adak Airport experiences some seasonal variation in monthly rainfall.
Rain falls throughout the year at Adak Airport. The most rain falls during the 31 days centered around August 26, with an average total accumulation of 3.1 inches.
The least rain falls around May 16, with and average total accumulation of 1.4 inches.
Average Monthly Rainfall
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Adak Airport experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.0 months, from November 29 to March 29, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 10, with an average total liquid-equivalent accumulation of 0.3 inches.
The snowless period of the year lasts for 8.0 months, from March 29 to November 29. The least snow falls around August 2, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day at Adak Airport varies extremely over the course of the year. In 2017, the shortest day is December 21, with 7 hours, 46 minutes of daylight; the longest day is June 21, with 16 hours, 43 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:26 AM on June 16, and the latest sunrise is 3 hours, 28 minutes later at 9:54 AM on December 30. The earliest sunset is at 5:35 PM on December 12, and the latest sunset is 5 hours, 35 minutes later at 11:10 PM on June 24.
Daylight saving time (DST) is observed at Adak Airport during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
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 perceived humidity level at Adak Airport, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
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 at Adak Airport experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 7.7 months, from September 16 to May 7, with average wind speeds of more than 9.1 miles per hour. The windiest day of the year is November 20, with an average hourly wind speed of 11.7 miles per hour.
The calmer time of year lasts for 4.3 months, from May 7 to September 16. The calmest day of the year is July 21, with an average hourly wind speed of 6.5 miles per hour.
Average Wind Speed
The predominant average hourly wind direction at Adak Airport varies throughout the year.
The wind is most often from the north for 1.2 months, from January 7 to February 13, with a peak percentage of 30% on January 21. The wind is most often from the east for 1.0 weeks, from February 13 to February 20 and for 1.0 weeks, from December 31 to January 7, with a peak percentage of 27% on February 19. The wind is most often from the west for 10 months, from February 20 to December 31, with a peak percentage of 45% on October 27.
Adak Airport is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature experiences some seasonal variation over the course of the year.
The time of year with warmer water lasts for 2.2 months, from July 23 to September 29, with an average temperature above 46°F. The day of the year with the warmest water is August 26, with an average temperature of 49°F.
The time of year with cooler water lasts for 5.2 months, from December 12 to May 19, with an average temperature below 41°F. The day of the year with the coolest water is February 21, with an average temperature of 39°F.
Average Water Temperature
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 experiences significant seasonal variation over the course of the year.
The brighter period of the year lasts for 3.9 months, from April 21 to August 17, with an average daily incident shortwave energy per square meter above 3.8 kWh. The brightest day of the year is May 29, with an average of 4.7 kWh.
The darker period of the year lasts for 3.6 months, from October 29 to February 18, with an average daily incident shortwave energy per square meter below 1.4 kWh. The darkest day of the year is December 22, with an average of 0.5 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Adak Airport are 51.878 deg latitude, -176.646 deg longitude, and 157 ft elevation.
The topography within 2 miles of Adak Airport contains significant variations in elevation, with a maximum elevation change of 663 feet and an average elevation above sea level of 124 feet. Within 10 miles contains significant variations in elevation (3,819 feet). Within 50 miles also contains extreme variations in elevation (5,889 feet).
The area within 2 miles of Adak Airport is covered by water (48%), shrubs (39%), and grassland (10%), within 10 miles by water (56%) and shrubs (28%), and within 50 miles by water (94%).
This report illustrates the typical weather at Adak Airport, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
Adak Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
In this case, the only station close and reliable enough to use as a fallback is Atka Airport.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.