December weather forecastSouth Portland, ME
December
Weather in December
December wraps up the year in South Portland with the full swing of the winter season. Amid cold spells, temperatures averaging at 36.5°F (2.5°C) define the city's snowy landscape. The city wears a tranquil blanket of white, with 2.28" (58mm) of snowfall adorning the scenery. Residents bundle up in warm layers as festive lamp posts and twinkling Christmas decorations light up the snowy nights. As South Portland embraces the chill of the season, winter festivities keep the spirits high, cherishing the snow-covered charm of the city.Temperature
As South Portland enters December, the average high-temperature decreases from the a frosty 46°F (7.8°C) of November to an icy 36.5°F (2.5°C). In South Portland, the month of December brings a consistent average low-temperature of 27.9°F (-2.3°C), slightly cooler than its daytime highs.Humidity
The average relative humidity in December in South Portland is 77%.Rainfall
In South Portland, in December, it is raining for 7.9 days, with typically 2.01" (51mm) of accumulated precipitation. In South Portland, during the entire year, the rain falls for 127 days and collects up to 21.93" (557mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 5.4 days. Throughout December, 2.28" (58mm) of snow is accumulated. Throughout the year, there are 29.7 snowfall days, and 11.73" (298mm) of snow is accumulated.Ocean temperature
In December, the average ocean temperature is 45.3°F (7.4°C).Note: Swimming in 45.3°F (7.4°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.
Daylight
December has the shortest days of the year, with an average of 9h and 0min of daylight.On the first day of the month, sunrise is at 6:55 am and sunset at 4:05 pm. On the last day of December, sunrise is at 7:14 am and sunset at 4:14 pm EST.
Sunshine
With an average of 4.8h of sunshine, December has the least sunshine of the year in South Portland.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in South Portland. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for the average person.Note: The maximum UV index of 2 during December leads to these instructions:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
South Portland, ME
- Average high temperature in December: 36.5°F
The warmest month (with the highest average high temperature) is July (72.5°F).
The month with the lowest average high temperature is January (31.1°F).
- Average low temperature in December: 27.9°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).
Average pressure in December
South Portland, ME
- Average pressure in December: 30.01"Hg
The months with the highest atmospheric pressure are September and November (30.05"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
South Portland, ME
- Average wind speed in December: 11.6mph
The windiest month (with the highest average wind speed) is January (12.5mph).
The calmest months (with the lowest average wind speed) are July and August (7.5mph).
Average humidity in December
South Portland, ME
- Average humidity in December: 77%
The months with the highest relative humidity are June and July (82%).
The month with the lowest relative humidity is November (74%).
Average rainfall in December
South Portland, ME
- Average rainfall in December: 2.01"
The wettest month (with the highest rainfall) is October (2.36").
The driest month (with the least rainfall) is September (1.18").
Average rainfall days in December
South Portland, ME
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is July (14.7 days).
The month with the least rainy days is January (5.7 days).
Average snowfall in December
South Portland, ME
- Average snowfall in December: 2.28"
The month with the highest snowfall is February (2.91").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
South Portland, ME
- Average snowfall days in December: 5.4 days
The month with the highest number of snowfall days is January (7.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in December
South Portland, ME
- Average sea temperature in December: 45.3°F
The best month for swimming (with the highest average sea temperature) is August (63.7°F).
The coldest month (with the lowest average sea temperature) is March (38°F).
Average daylight in December /
Average sunshine in December
South Portland, ME
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 4h and 48min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 48min).
Average sunshine days in December
South Portland, ME
- Average sunshine days in December: 17.6 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is July (13.8 days).
Average UV index in December
South Portland, ME
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in December
South Portland, ME
- Average cloud cover in December: 48
The month with the most cloud cover is March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in December
South Portland, ME
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
