December weather forecastPortland, ME
December
Weather in December
Coming to the end of the year, Portland, Maine experiences significant drops in temperature, ranging from 36.5°F (2.5°C) to 27.9°F (-2.3°C). December sees an introduction of snowy landscapes painting the city white. Christmas lights twinkle, and holiday decorations spruce up the city, lifting spirits despite the chill. Warm clothes and hot drinks serve as constant companions in tackling the cold weather. So be sure to wrap up warmly and enjoy the winter magic in the most festive month of the year.Temperature
During the transition into December, Portland observes a decrease in the average high-temperature, falling from a frosty 46°F (7.8°C) in November to an icy 36.5°F (2.5°C). A modest dip in temperatures to an average of 27.9°F (-2.3°C) is observed throughout Portland's December nights.Humidity
In Portland, the average relative humidity in December is 77%.Rainfall
In December, the rain falls for 7.9 days. Throughout December, 2.01" (51mm) of precipitation is accumulated. In Portland, during the entire year, the rain falls for 127 days and collects up to 21.93" (557mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Portland, Maine, during December, snow falls for 5.4 days and regularly aggregates up to 2.28" (58mm) of snow. Throughout the year, in Portland, there are 29.7 snowfall days, and 11.73" (298mm) of snow is accumulated.Ocean temperature
In Portland, Maine, in December, the average water temperature is 45.3°F (7.4°C).Note: Staying in 45.3°F (7.4°C) waters for just a few moments at 55.4°F (13°C) can be harrowing, and below 50°F (10°C) poses breathing and cold shock risks, depending on individual tolerance.
Daylight
With an average of 9h and 0min of daylight, December has the shortest days of the year.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, in Portland, sunrise is at 7:14 am and sunset at 4:14 pm EST.
Sunshine
The month with the least sunshine in Portland is December, with an average of 4.8h of sunshine.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for the average person.Note: In December, a daily UV index of 2 turns into the following recommendations:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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).
