Average Weather in December in Dutch Harbor Alaska, United States
Daily high temperatures decrease by 2°F, from 39°F to 37°F, rarely falling below 31°F or exceeding 45°F.
Daily low temperatures decrease by 2°F, from 34°F to 32°F, rarely falling below 24°F or exceeding 39°F.
For reference, on August 13, the hottest day of the year, temperatures in Dutch Harbor typically range from 50°F to 57°F, while on January 23, the coldest day of the year, they range from 31°F to 36°F.
Average High and Low Temperature in December
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on December. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in December
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The month of December in Dutch Harbor experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 71% to 76%.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 29% of the time.
For reference, on July 13, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 82%, while on October 13, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 41%.
Cloud Cover Categories in December
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Dutch Harbor, the chance of a wet day over the course of December is decreasing, starting the month at 45% and ending it at 41%.
For reference, the year's highest daily chance of a wet day is 48% on December 16, and its lowest chance is 25% on May 4.
Over the course of December in Dutch Harbor, the chance of a day with only rain decreases from 41% to 34%, the chance of a day with mixed snow and rain remains an essentially constant 3% throughout, and the chance of a day with only snow remains an essentially constant 2% throughout.
Probability of Precipitation in December
To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during December in Dutch Harbor is gradually decreasing, starting the month at 3.9 inches, when it rarely exceeds 5.9 inches or falls below 1.8 inches, and ending the month at 3.6 inches, when it rarely exceeds 5.9 inches or falls below 1.5 inches.
The highest average 31-day accumulation is 4.0 inches on December 8.
Average Monthly Rainfall in December
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. As with rainfall, we consider the liquid-equivalent snowfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day liquid-equivalent snowfall during December in Dutch Harbor is essentially constant, remaining about 0.3 inches throughout, and rarely exceeding 1.2 inches or falling below -0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Dutch Harbor, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 16 minutes, implying an average daily decrease of 31 seconds, and weekly decrease of 3 minutes, 37 seconds.
The shortest day of the month is December 20, with 7 hours, 24 minutes of daylight and the longest day is December 1, with 7 hours, 46 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Dutch Harbor is 9:02 AM on December 1 and the latest sunrise is 22 minutes later at 9:24 AM on December 29.
The earliest sunset is 4:44 PM on December 13 and the latest sunset is 11 minutes later at 4:54 PM on December 31.
Daylight saving time is observed in Dutch Harbor during 2020, but it neither starts nor ends during December, so the entire month is in standard time.
For reference, on June 20, the longest day of the year, the Sun rises at 5:34 AM and sets 17 hours, 7 minutes later, at 10:41 PM, while on December 21, the shortest day of the year, it rises at 9:22 AM and sets 7 hours, 24 minutes later, at 4:46 PM.
Sunrise & Sunset with Twilight in December
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 chance that a given day will be muggy in Dutch Harbor is essentially constant during December, remaining around 0% throughout.
For reference, on July 9, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in December
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 in Dutch Harbor is gradually decreasing during December, decreasing from 19.8 miles per hour to 19.1 miles per hour over the course of the month.
For reference, on November 24, the windiest day of the year, the daily average wind speed is 20.1 miles per hour, while on July 17, the calmest day of the year, the daily average wind speed is 11.2 miles per hour.
Average Wind Speed in December
The wind direction in Dutch Harbor during December is predominantly out of the west from December 1 to December 21 and the north from December 21 to December 31.
Wind Direction in December
Dutch Harbor 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 surface water temperature in Dutch Harbor is essentially constant during December, remaining within 1°F of 41°F throughout.
Average Water Temperature in December
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 in Dutch Harbor typically lasts for 6.7 months (205 days), from around April 23 to around November 15, rarely starting before April 2 or after May 11, and rarely ending before October 19 or after December 19.
The month of December in Dutch Harbor is more likely than not fully outside of the growing season, with the chance that a given day is in the growing season rapidly decreasing from 25% to 5% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in December
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
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.
The average accumulated growing degree days in Dutch Harbor are essentially constant during December, remaining around 191°F throughout.
Growing Degree Days in December
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 in Dutch Harbor is essentially constant during December, remaining within 0.1 kWh of 0.5 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 0.4 kWh on December 15.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Dutch Harbor are 53.890 deg latitude, -166.542 deg longitude, and 0 ft elevation.
The topography within 2 miles of Dutch Harbor contains very significant variations in elevation, with a maximum elevation change of 1,611 feet and an average elevation above sea level of 130 feet. Within 10 miles contains very significant variations in elevation (3,533 feet). Within 50 miles also contains extreme variations in elevation (5,971 feet).
The area within 2 miles of Dutch Harbor is covered by water (76%), within 10 miles by water (41%) and shrubs (24%), and within 50 miles by water (86%).
This report illustrates the typical weather in Dutch Harbor year round, 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
There is only a single weather station, Unalaska Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Dutch Harbor.
At a distance of 1 kilometers from Dutch Harbor, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.
The station records are corrected for the elevation difference between the station and Dutch Harbor according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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.