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December Weather in Petersburg Alaska, United States

Daily high temperatures decrease by 2°F, from 37°F to 35°F, rarely falling below 22°F or exceeding 46°F. The lowest daily average high temperature is 35°F on December 31.

Daily low temperatures decrease by 2°F, from 29°F to 27°F, rarely falling below 11°F or exceeding 38°F. The lowest daily average low temperature is 27°F on December 31.

For reference, on July 30, the hottest day of the year, temperatures in Petersburg typically range from 51°F to 64°F, while on December 31, the coldest day of the year, they range from 27°F to 35°F.

Average High and Low Temperature in December in Petersburg

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 Petersburg

Average Hourly Temperature in December in PetersburgDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 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 AMNovJanfreezingfreezingvery 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 average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Ytre Arna, Norway (4,028 miles away) is the far-away foreign place with temperatures most similar to Petersburg (view comparison).

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The month of December in Petersburg experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 77% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 75% on December 31.

The clearest day of the month is December 31, with clear, mostly clear, or partly cloudy conditions 25% of the time.

For reference, on October 21, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 81%, while on May 26, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 33%.

Cloud Cover Categories in December in Petersburg

Cloud Cover Categories in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJanOct 2119%Oct 2119%Dec 121%Dec 121%Dec 3125%Dec 3125%Dec 1122%Dec 1122%Dec 2123%Dec 2123%clearpartly cloudymostly cloudyovercastmostly clear
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 Petersburg, the chance of a wet day over the course of December is rapidly decreasing, starting the month at 69% and ending it at 62%.

For reference, the year's highest daily chance of a wet day is 75% on October 22, and its lowest chance is 42% on May 27.

Over the course of December in Petersburg, the chance of a day with only rain decreases from 49% to 41%, the chance of a day with mixed snow and rain remains an essentially constant 16% throughout, and the chance of a day with only snow increases from 5% to 7%.

Probability of Precipitation in December in Petersburg

Probability of Precipitation in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%NovJanDec 169%Dec 169%Dec 3162%Dec 3162%Dec 1167%Dec 1167%Dec 2164%Dec 2164%snowmixedrain
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 Petersburg is rapidly decreasing, starting the month at 11.5 inches, when it rarely exceeds 18.2 inches or falls below 5.2 inches, and ending the month at 10.1 inches, when it rarely exceeds 16.2 inches or falls below 4.6 inches.

Average Monthly Rainfall in December in Petersburg

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 Petersburg is rapidly increasing, starting the month at 10.0 inches, when it rarely exceeds 26.9 inches or falls below 1.4 inches, and ending the month at 13.6 inches, when it rarely exceeds 34.1 inches or falls below 1.8 inches.

Average Monthly Snowfall in December in Petersburg

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 Petersburg, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 18 minutes, implying an average daily decrease of 37 seconds, and weekly decrease of 4 minutes, 18 seconds.

The shortest day of the month is December 21, with 6 hours, 45 minutes of daylight and the longest day is December 1, with 7 hours, 12 minutes of daylight.

Hours of Daylight and Twilight in December in Petersburg

Hours of Daylight and Twilight in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrNovJanDec 216 hr, 45 minDec 216 hr, 45 minnightnightdaydayDec 17 hr, 12 minDec 17 hr, 12 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 Petersburg is 8:05 AM on December 1 and the latest sunrise is 24 minutes later at 8:29 AM on December 27.

The earliest sunset is 3:11 PM on December 14 and the latest sunset is 11 minutes later at 3:22 PM on December 31.

Daylight saving time is observed in Petersburg 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 3:58 AM and sets 17 hours, 50 minutes later, at 9:48 PM, while on December 21, the shortest day of the year, it rises at 8:27 AM and sets 6 hours, 45 minutes later, at 3:13 PM.

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

Sunrise & Sunset with Twilight and Daylight Saving Time in December in PetersburgDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMNovJan8:05 AM8:05 AMDec 13:16 PMDec 13:16 PM8:28 AM8:28 AMDec 313:22 PMDec 313:22 PM8:22 AM8:22 AMDec 143:11 PMDec 143:11 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 Petersburg

Solar Elevation and Azimuth in December in PetersburgDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 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 AMNovJan001010001010
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 Petersburg

Moon Rise, Set & Phases in December in PetersburgDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 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 AM8:38 AM8:38 AM4:40 PM4:40 PM2:56 PM2:56 PM9:36 AM9:36 AM8:11 AM8:11 AM2:14 PM2:14 PM1:46 PM1:46 PM9:27 AM9:27 AM2:21 PM2:21 PM2:58 PM2:58 PM9:29 AM9:29 AM8:39 AM8:39 AM4:31 PM4:31 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%9:34 AMSSE2:40 PMSSW-12:07 PMS245,042 mi
2
3%10:43 AMSSE3:26 PMSSW-1:05 PMS242,946 mi
3
7%11:30 AMSSE4:36 PMSSW-2:03 PMS240,807 mi
4
14%11:58 AMSE6:04 PMSW-3:01 PMS238,659 mi
5
23%12:14 PMSE7:39 PMSW-3:56 PMS236,520 mi
6
33%12:24 PMESE9:14 PMWSW-4:48 PMS234,409 mi
7
44%12:30 PMESE10:47 PMWSW-5:37 PMS232,368 mi
8
50%12:35 PME--6:24 PMS230,475 mi
9
67%-12:19 AMW12:40 PME7:11 PMS228,852 mi
10
78%-1:53 AMW12:45 PMENE7:59 PMS227,657 mi
11
87%-3:30 AMWNW12:51 PMENE8:51 PMS227,063 mi
12
94%-5:11 AMNW1:01 PMNE9:45 PMS227,227 mi
13
99%-6:55 AMNW1:17 PMNE10:44 PMS228,247 mi
14
100%-8:35 AMNNW1:46 PMNNE11:45 PMS230,127 mi
15
100%-9:54 AMNNW2:39 PMNNE--
16
99%-10:43 AMNNW3:58 PMNNE12:47 AMS232,758 mi
17
95%-11:10 AMNW5:30 PMNE1:45 AMS235,927 mi
18
89%-11:24 AMNW7:02 PMNE2:39 AMS239,356 mi
19
81%-11:33 AMWNW8:29 PMENE3:27 AMS242,747 mi
20
72%-11:38 AMWNW9:52 PMENE4:11 AMS245,823 mi
21
63%-11:42 AMW11:10 PME4:52 AMS248,352 mi
22
50%-11:46 AMW-5:31 AMS250,162 mi
23
44%12:26 AME11:49 AMW-6:10 AMS251,151 mi
24
34%1:43 AMESE11:53 AMWSW-6:49 AMS251,287 mi
25
25%3:02 AMESE11:58 AMWSW-7:31 AMS250,605 mi
26
17%4:24 AMSE12:05 PMSW-8:15 AMS249,203 mi
27
10%5:49 AMSE12:18 PMSW-9:04 AMS247,227 mi
28
5%7:15 AMSE12:39 PMSSW-9:57 AMS244,861 mi
29
1%8:31 AMSSE1:18 PMSSW-10:54 AMS242,305 mi
30
0%9:27 AMSSE2:21 PMSSW-11:54 AMS239,758 mi
31
1%10:01 AMSE3:46 PMSW-12:53 PMS237,388 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 Petersburg is essentially constant during December, remaining around 0% throughout.

For reference, on June 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 in Petersburg

Humidity Comfort Levels in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%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 Petersburg is essentially constant during December, remaining within 0.1 miles per hour of 9.0 miles per hour throughout.

For reference, on January 2, the windiest day of the year, the daily average wind speed is 9.2 miles per hour, while on July 17, the calmest day of the year, the daily average wind speed is 4.3 miles per hour.

Average Wind Speed in December in Petersburg

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 Petersburg throughout December is predominantly from the east, with a peak proportion of 64% on December 31.

Wind Direction in December in Petersburg

Wind Direction in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%NovJansoutheastwestnorth
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).

Petersburg 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 Petersburg is essentially constant during December, remaining within 1°F of 44°F throughout.

Average Water Temperature in December in Petersburg

Average Water Temperature in December in PetersburgDec112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313139°F39°F40°F40°F41°F41°F42°F42°F43°F43°F44°F44°F45°F45°F46°F46°F47°F47°F48°F48°F49°F49°FNovJanDec 144°FDec 144°FDec 3143°FDec 3143°FDec 1144°FDec 1144°FDec 2143°FDec 2143°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 Petersburg typically lasts for 5.9 months (180 days), from around April 24 to around October 21, rarely starting before April 8 or after May 13, and rarely ending before September 28 or after November 11.

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

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

Time Spent in Various Temperature Bands and the Growing Season in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%NovJan0%Dec 160%Dec 16Nov 1110%Nov 1110%freezingvery coldcoldfrigid
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 Petersburg are essentially constant during December, remaining around 659°F throughout.

Growing Degree Days in December in Petersburg

Growing Degree Days in December in PetersburgDec1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131500°F500°F550°F550°F600°F600°F650°F650°F700°F700°F750°F750°F800°F800°F850°F850°FNovJanDec 1659°FDec 1659°FDec 31659°FDec 31659°FDec 11659°FDec 11659°FDec 21659°FDec 21659°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 Petersburg is essentially constant during December, remaining around 0.3 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 0.3 kWh on December 19.

Average Daily Incident Shortwave Solar Energy in December in Petersburg

Average Daily Incident Shortwave Solar Energy in December in PetersburgDec11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310.0 kWh0.0 kWh0.2 kWh0.2 kWh0.4 kWh0.4 kWh0.6 kWh0.6 kWh0.8 kWh0.8 kWh1.0 kWh1.0 kWh1.2 kWh1.2 kWh1.4 kWh1.4 kWh1.6 kWh1.6 kWhNovJanDec 190.3 kWhDec 190.3 kWhDec 10.4 kWhDec 10.4 kWhDec 310.3 kWhDec 310.3 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 Petersburg are 56.812 deg latitude, -132.956 deg longitude, and 36 ft elevation.

The topography within 2 miles of Petersburg contains large variations in elevation, with a maximum elevation change of 2,169 feet and an average elevation above sea level of 167 feet. Within 10 miles contains large variations in elevation (3,812 feet). Within 50 miles also contains extreme variations in elevation (10,026 feet).

The area within 2 miles of Petersburg is covered by trees (48%), water (39%), and sparse vegetation (12%), within 10 miles by trees (63%) and water (27%), and within 50 miles by trees (40%) and water (28%).

This report illustrates the typical weather in Petersburg, 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Petersburg.

For each station, the records are corrected for the elevation difference between that station and Petersburg 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 Petersburg is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Petersburg 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 Petersburg 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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