Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The coldest temperatures occur during December, when averages reach a peak of 44.1°F (6.7°C) and a low of 34.7°F (1.5°C).Humidity
January, February and December, with an average relative humidity of 83%, are the most humid months.Rainfall
December is the month with the most rainfall. Rain falls for 18.5 days and accumulates 4.53" (115mm) of precipitation.Snowfall
Months with snowfall in Portland are January through March, November and December. In Portland, in December, snow falls for 0.8 days, with typically accumulated 0.28" (7mm) of snow. Throughout the year, there are 6.4 snowfall days, and 3.94" (100mm) of snow is accumulated.Daylight
With an average of 8h and 48min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:31 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:50 am and sunset at 4:37 pm PST.
Sunshine
The average sunshine in December is 4.3h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The daily high UV index of 2 during December translates into the following recommendations:
Sun exposure does not present considerable issues for many, yet infants, fair-skinned people, and children necessitate constant protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month?
Is December cold?
What are the most humid months?
What is the average humidity in December?
What is the rainiest month?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Portland have in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Portland have in December?
What is the month with the lowest UV index?
What is the UV index intensity in December in Portland?
Average temperature in December
Portland, OR
- Average high temperature in December: 44.1°F
The warmest month (with the highest average high temperature) is August (81.5°F).
The month with the lowest average high temperature is December (44.1°F).
- Average low temperature in December: 34.7°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (34.7°F).
Average pressure in December
Portland, OR
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in December
Portland, OR
- Average wind speed in December: 5.5mph
The windiest month (with the highest average wind speed) is January (5.8mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).
Average humidity in December
Portland, OR
- Average humidity in December: 83%
The months with the highest relative humidity are January, February and December (83%).
The month with the lowest relative humidity is August (63%).
Average rainfall in December
Portland, OR
- Average rainfall in December: 4.53"
The wettest month (with the highest rainfall) is December (4.53").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in December
Portland, OR
- Average rainfall days in December: 18.5 days
The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is July (4.9 days).
Average snowfall in December
Portland, OR
- Average snowfall in December: 0.28"
The month with the highest snowfall is March (1.5").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Portland, OR
- Average snowfall days in December: 0.8 days
The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Portland, OR
- Average daylight in December: 8h and 5min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Portland, OR
- Average sunshine days in December: 10.5 days
The months with the most sunshine days are July and August (23.8 days).
The month with the least sunshine days is March (8.3 days).
Average UV index in December
Portland, OR
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Portland, OR
- Average cloud cover in December: 56
The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 23).
Average visibility in December
Portland, OR
- Average visibility in December: 5mi
The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, May, June, October, November and December (5mi).
Portland, Oregon, USA
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