Average Weather at Eielson Air Force Base Alaska, United States
At Eielson Air Force Base, the summers are long, comfortable, and mostly cloudy and the winters are frigid, snowy, and partly cloudy. Over the course of the year, the temperature typically varies from -14°F to 73°F and is rarely below -40°F or above 83°F.
Based on the tourism score, the best time of year to visit Eielson Air Force Base for warm-weather activities is from late June to late July.
The warm season lasts for 4.0 months, from May 11 to September 9, with an average daily high temperature above 59°F. The hottest day of the year is July 4, with an average high of 73°F and low of 52°F.
The cold season lasts for 3.6 months, from November 7 to February 25, with an average daily high temperature below 16°F. The coldest day of the year is January 18, with an average low of -14°F and high of 2°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
Kotik, Russia (3,459 miles away); Зуунмод, Mongolia (3,727 miles); and Mogzon, Russia (3,372 miles) are the far-away foreign places with temperatures most similar to Eielson Air Force Base (view comparison).
At Eielson Air Force Base, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.
The clearer part of the year at Eielson Air Force Base begins around February 15 and lasts for 1.7 months, ending around April 6. On March 16, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 46% of the time, and overcast or mostly cloudy 54% of the time.
The cloudier part of the year begins around April 6 and lasts for 10 months, ending around February 15. On September 26, the cloudiest day of the year, the sky is overcast or mostly cloudy 65% of the time, and clear, mostly clear, or partly cloudy 35% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Eielson Air Force Base varies throughout the year.
The wetter season lasts 4.5 months, from May 24 to October 9, with a greater than 19% chance of a given day being a wet day. The chance of a wet day peaks at 33% on July 12.
The drier season lasts 7.5 months, from October 9 to May 24. The smallest chance of a wet day is 5% on March 22.
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 at Eielson Air Force Base changes throughout the year.
Rain alone is the most common for 6.0 months, from April 14 to October 15. The highest chance of a day with rain alone is 33% on July 12.
Snow alone is the most common for 5.9 months, from October 15 to April 14. The highest chance of a day with snow alone is 12% on January 3.
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. Eielson Air Force Base experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 5.4 months, from May 3 to October 17, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around July 11, with an average total accumulation of 2.7 inches.
The rainless period of the year lasts for 6.6 months, from October 17 to May 3. The least rain falls around December 25, with an average total accumulation of 0.0 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. Eielson Air Force Base experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 7.1 months, from September 20 to April 24, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around November 23, with an average total liquid-equivalent accumulation of 0.5 inches.
The snowless period of the year lasts for 4.9 months, from April 24 to September 20. The least snow falls around July 16, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day at Eielson Air Force Base varies extremely over the course of the year. In 2018, the shortest day is December 21, with 3 hours, 48 minutes of daylight; the longest day is June 21, with 21 hours, 39 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 3:00 AM on June 20, and the latest sunrise is 7 hours, 53 minutes later at 10:53 AM on December 24. The earliest sunset is at 2:39 PM on December 18, and the latest sunset is 9 hours, 60 minutes later at 12:39 AM on June 21.
Daylight saving time (DST) is observed at Eielson Air Force Base during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
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 Eielson Air Force Base, 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 Eielson Air Force Base experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.6 months, from November 10 to March 28, with average wind speeds of more than 5.8 miles per hour. The windiest day of the year is January 8, with an average hourly wind speed of 7.2 miles per hour.
The calmer time of year lasts for 7.4 months, from March 28 to November 10. The calmest day of the year is July 14, with an average hourly wind speed of 4.3 miles per hour.
Average Wind Speed
The predominant average hourly wind direction at Eielson Air Force Base varies throughout the year.
The wind is most often from the west for 3.9 months, from May 10 to September 6, with a peak percentage of 52% on July 6. The wind is most often from the east for 8.1 months, from September 6 to May 10, with a peak percentage of 65% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is at Eielson Air Force Base throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Eielson Air Force Base for general outdoor tourist activities is from late June to late July, with a peak score in the second week of July.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Eielson Air Force Base for hot-weather activities is from late June to mid July, with a peak score in the first week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
The growing season at Eielson Air Force Base typically lasts for 3.8 months (115 days), from around May 14 to around September 7, rarely starting before April 30 or after May 30, and rarely ending before August 18 or after September 26.
Time Spent in Various Temperature Bands and the Growing Season
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
Based on growing degree days alone, the first spring blooms at Eielson Air Force Base should appear around May 21, only rarely appearing before May 13 or after June 1.
Growing Degree Days
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 extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.2 months, from April 28 to August 2, with an average daily incident shortwave energy per square meter above 4.5 kWh. The brightest day of the year is June 21, with an average of 5.6 kWh.
The darker period of the year lasts for 4.4 months, from October 14 to February 24, with an average daily incident shortwave energy per square meter below 1.1 kWh. The darkest day of the year is December 22, with an average of 0.0 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Eielson Air Force Base are 64.664 deg latitude, -147.099 deg longitude, and 545 ft elevation.
The topography within 2 miles of Eielson Air Force Base is essentially flat, with a maximum elevation change of 56 feet and an average elevation above sea level of 540 feet. Within 10 miles is essentially flat (1,522 feet). Within 50 miles contains very significant variations in elevation (6,076 feet).
The area within 2 miles of Eielson Air Force Base is covered by trees (51%), sparse vegetation (30%), and artificial surfaces (12%), within 10 miles by trees (75%), and within 50 miles by trees (68%) and shrubs (21%).
This report illustrates the typical weather at Eielson Air Force Base, 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
Eielson Air Force Base 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.
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.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.