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December Weather in Anchorage Alaska, United States

Daily high temperatures are around 24°F, rarely falling below 7°F or exceeding 38°F. The lowest daily average high temperature is 23°F on December 29.

Daily low temperatures decrease by 2°F, from 15°F to 13°F, rarely falling below -6°F or exceeding 30°F.

For reference, on July 19, the hottest day of the year, temperatures in Anchorage typically range from 55°F to 68°F, while on January 17, the coldest day of the year, they range from 13°F to 23°F.

Average High and Low Temperature in December in Anchorage

Average High and Low Temperature in December in AnchorageDec1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131-10°F-10°F-5°F-5°F0°F0°F5°F5°F10°F10°F15°F15°F20°F20°F25°F25°F30°F30°F35°F35°F40°F40°F45°F45°FNovJanDec 2823°FDec 2823°F13°F13°FDec 125°FDec 125°F15°F15°FDec 1124°FDec 1124°F15°F15°F
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

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 in Anchorage

Average Hourly Temperature in December in AnchorageDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNovJanfreezing
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 average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Lena, Norway (3,957 miles away) and Petrozavodsk, Russia (3,939 miles) are the far-away foreign places with temperatures most similar to Anchorage (view comparison).

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The month of December in Anchorage experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 61% throughout the month. The highest chance of overcast or mostly cloudy conditions is 63% on December 17.

The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 41% of the time.

For reference, on December 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 63%, while on March 15, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 48%.

Cloud Cover Categories in December in Anchorage

Cloud Cover Categories in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJanMar 1548%Mar 1548%Dec 141%Dec 141%Dec 3140%Dec 3140%Dec 1139%Dec 1139%Dec 2138%Dec 2138%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Anchorage, the chance of a wet day over the course of December is essentially constant, remaining around 24% throughout.

For reference, the year's highest daily chance of a wet day is 39% on September 26, and its lowest chance is 13% on March 27.

Over the course of December in Anchorage, the chance of a day with only rain remains an essentially constant 4% throughout, the chance of a day with mixed snow and rain remains an essentially constant 4% throughout, and the chance of a day with only snow remains an essentially constant 16% throughout.

Probability of Precipitation in December in Anchorage

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

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 Anchorage is essentially constant, remaining about 0.4 inches throughout, and rarely exceeding 1.5 inches.

Average Monthly Rainfall in December in Anchorage

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day snowfall during December in Anchorage is gradually decreasing, starting the month at 9.5 inches, when it rarely exceeds 18.8 inches or falls below 2.8 inches, and ending the month at 8.6 inches, when it rarely exceeds 16.2 inches or falls below 2.4 inches.

The highest average 31-day accumulation is 9.7 inches on December 11.

Average Monthly Snowfall in December in Anchorage

The average snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Over the course of December in Anchorage, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 25 minutes, implying an average daily decrease of 50 seconds, and weekly decrease of 5 minutes, 51 seconds.

The shortest day of the month is December 21, with 5 hours, 27 minutes of daylight and the longest day is December 1, with 6 hours, 3 minutes of daylight.

Hours of Daylight and Twilight in December in Anchorage

Hours of Daylight and Twilight in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrNovJanDec 215 hr, 27 minDec 215 hr, 27 minnightnightdaydayDec 16 hr, 3 minDec 16 hr, 3 min
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in Anchorage is 9:47 AM on December 1 and the latest sunrise is 29 minutes later at 10:15 AM on December 26.

The earliest sunset is 3:40 PM on December 15 and the latest sunset is 12 minutes later at 3:52 PM on December 31.

Daylight saving time is observed in Anchorage during 2024, but it neither starts nor ends during December, so the entire month is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 4:20 AM and sets 19 hours, 23 minutes later, at 11:42 PM, while on December 21, the shortest day of the year, it rises at 10:14 AM and sets 5 hours, 27 minutes later, at 3:41 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in December in Anchorage

Sunrise & Sunset with Twilight and Daylight Saving Time in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031312 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMNovJan9:47 AM9:47 AMDec 13:50 PMDec 13:50 PM10:14 AM10:14 AMDec 313:52 PMDec 313:52 PM10:10 AM10:10 AMDec 153:40 PMDec 153:40 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of December. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in December in Anchorage

Solar Elevation and Azimuth in December in AnchorageDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNovJan0000
northeastsouthwest
Solar elevation and azimuth over the course of December 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for December 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in December in Anchorage

Moon Rise, Set & Phases in December in AnchorageDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNovJanNov 14:48 AMNov 14:48 AMNov 1512:29 PMNov 1512:29 PMNov 309:22 PMNov 309:22 PMDec 1512:02 AMDec 1512:02 AMDec 301:28 PMDec 301:28 PMJan 131:28 PMJan 131:28 PMJan 293:37 AMJan 293:37 AM10:18 AM10:18 AM5:18 PM5:18 PM3:27 PM3:27 PM10:17 AM10:17 AM2:27 PM2:27 PM1:36 PM1:36 PM3:12 PM3:12 PM11:17 AM11:17 AM10:19 AM10:19 AM5:14 PM5:14 PM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
Dec 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
0%12:06 PMSSE2:28 PMSSW-1:17 PMS244,945 mi
2
3%1:36 PMS2:54 PMS-2:15 PMS242,846 mi
3
8%1:59 PMSSE4:30 PMSSW-3:14 PMS240,705 mi
4
15%2:00 PMSSE6:25 PMSSW-4:12 PMS238,557 mi
5
23%1:58 PMSE8:17 PMSW-5:07 PMS236,418 mi
6
33%1:55 PMSE10:05 PMWSW-5:59 PMS234,309 mi
7
45%1:52 PMESE11:48 PMWSW-6:48 PMS232,273 mi
8
50%1:49 PME--7:35 PMS230,390 mi
9
68%-1:30 AMW1:45 PME8:23 PMS228,783 mi
10
79%-3:13 AMWNW1:42 PMENE9:11 PMS227,613 mi
11
88%-5:00 AMWNW1:39 PMENE10:02 PMS227,052 mi
12
94%-6:55 AMNW1:36 PMNE10:57 PMS227,255 mi
13
99%-8:58 AMNNW1:34 PMNNE11:55 PMS228,317 mi
14
100%-11:06 AMNNW1:36 PMNNE--
15
100%-12:47 PMN2:08 PMN12:56 AMS230,236 mi
16
98%-1:07 PMNNW3:56 PMNNE1:57 AMS232,897 mi
17
94%-1:08 PMNNW5:54 PMNNE2:55 AMS236,084 mi
18
88%-1:06 PMNW7:43 PMNE3:48 AMS239,517 mi
19
81%-1:03 PMNW9:21 PMENE4:36 AMS242,899 mi
20
72%-1:00 PMWNW10:52 PMENE5:20 AMS245,954 mi
21
62%-12:56 PMW-6:01 AMS248,453 mi
22
50%12:18 AME12:53 PMW-6:40 AMS250,226 mi
23
43%1:42 AME12:50 PMWSW-7:19 AMS251,176 mi
24
34%3:07 AMESE12:46 PMWSW-7:58 AMS251,273 mi
25
25%4:34 AMESE12:43 PMSW-8:40 AMS250,555 mi
26
17%6:08 AMSE12:40 PMSW-9:24 AMS249,123 mi
27
10%7:49 AMSSE12:38 PMSSW-10:13 AMS247,124 mi
28
5%9:36 AMSSE12:38 PMSSW-11:07 AMS244,744 mi
29
1%11:20 AMS12:50 PMS-12:05 PMS242,184 mi
30
0%12:05 PMSSE2:04 PMSSW-1:05 PMS239,641 mi
31
1%12:10 PMSSE3:59 PMSSW-2:04 PMS237,283 mi

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 Anchorage is essentially constant during December, remaining around 0% throughout.

For reference, on June 18, 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 in Anchorage

Humidity Comfort Levels in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%NovJanDec 10%Dec 10%Dec 310%Dec 310%Dec 110%Dec 110%Dec 210%Dec 210%drydry
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

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 Anchorage is essentially constant during December, remaining within 0.2 miles per hour of 6.2 miles per hour throughout.

For reference, on January 8, the windiest day of the year, the daily average wind speed is 6.6 miles per hour, while on July 5, the calmest day of the year, the daily average wind speed is 4.2 miles per hour.

Average Wind Speed in December in Anchorage

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Anchorage throughout December is predominantly from the east, with a peak proportion of 48% on December 18.

Wind Direction in December in Anchorage

Wind Direction in December in AnchorageNEDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%NovJaneastnorthsouth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Anchorage 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 Anchorage is gradually decreasing during December, falling by 2°F, from 35°F to 33°F, over the course of the month.

Average Water Temperature in December in Anchorage

Average Water Temperature in December in AnchorageDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313130°F30°F32°F32°F34°F34°F36°F36°F38°F38°F40°F40°F42°F42°F44°F44°FNovJanDec 135°FDec 135°FDec 3133°FDec 3133°FDec 1134°FDec 1134°FDec 2133°FDec 2133°F
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

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 Anchorage typically lasts for 5.1 months (156 days), from around April 24 to around September 28, rarely starting before April 9 or after May 11, and rarely ending before September 10 or after October 14.

The month of December in Anchorage is reliably fully outside of the growing season.

Time Spent in Various Temperature Bands and the Growing Season in December in Anchorage

Time Spent in Various Temperature Bands and the Growing Season in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJan-0%Dec 16-0%Dec 160%Nov 290%Nov 29frigidfreezingvery cold
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 percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within 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.

The average accumulated growing degree days in Anchorage are essentially constant during December, remaining around 976°F throughout.

Growing Degree Days in December in Anchorage

Growing Degree Days in December in AnchorageDec1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131750°F750°F800°F800°F850°F850°F900°F900°F950°F950°F1,000°F1,000°F1,050°F1,050°F1,100°F1,100°F1,150°F1,150°F1,200°F1,200°FNovJanDec 1976°FDec 1976°FDec 31976°FDec 31976°FDec 11976°FDec 11976°FDec 21976°FDec 21976°F
The average growing degree days accumulated over the course of December, with 25th to 75th and 10th to 90th percentile bands.

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 Anchorage is essentially constant during December, remaining around 0.2 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 0.1 kWh on December 20.

Average Daily Incident Shortwave Solar Energy in December in Anchorage

Average Daily Incident Shortwave Solar Energy in December in AnchorageDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310.0 kWh0.0 kWh0.1 kWh0.1 kWh0.2 kWh0.2 kWh0.3 kWh0.3 kWh0.4 kWh0.4 kWh0.5 kWh0.5 kWh0.6 kWh0.6 kWh0.7 kWh0.7 kWh0.8 kWh0.8 kWh0.9 kWh0.9 kWh1.0 kWh1.0 kWh1.1 kWh1.1 kWh1.2 kWh1.2 kWhNovJanDec 200.1 kWhDec 200.1 kWhDec 10.2 kWhDec 10.2 kWhDec 310.2 kWhDec 310.2 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

For the purposes of this report, the geographical coordinates of Anchorage are 61.218 deg latitude, -149.900 deg longitude, and 98 ft elevation.

The topography within 2 miles of Anchorage contains only modest variations in elevation, with a maximum elevation change of 177 feet and an average elevation above sea level of 48 feet. Within 10 miles contains only modest variations in elevation (3,212 feet). Within 50 miles contains large variations in elevation (7,936 feet).

The area within 2 miles of Anchorage is covered by artificial surfaces (79%) and sparse vegetation (14%), within 10 miles by water (29%) and trees (22%), and within 50 miles by trees (32%) and shrubs (21%).

This report illustrates the typical weather in Anchorage, 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 are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Anchorage.

For each station, the records are corrected for the elevation difference between that station and Anchorage according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Anchorage is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Anchorage and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of Anchorage and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

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 airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

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.

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