December weather forecastO'Brien, OR
December
Weather in December
December, the first month of the winter in O'Brien, is still a cool month, with temperature in the range of an average low of 40.6°F (4.8°C) and an average high of 50.4°F (10.2°C).Temperature
O'Brien experiences its lowest temperatures in December, with an average peak of 50.4°F (10.2°C) and a low of 40.6°F (4.8°C).Humidity
In December, the average relative humidity is 80%.Rainfall
In December, the rain falls for 17 days. Throughout December, 7.44" (189mm) of precipitation is accumulated. In O'Brien, during the entire year, the rain falls for 131.8 days and collects up to 46.14" (1172mm) of precipitation.Snowfall
January, March through December are months without snowfall.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of the month, sunrise is at 7:24 am and sunset at 4:44 pm. On the last day of December, sunrise is at 7:42 am and sunset at 4:53 pm PST.
Sunshine
With an average of 4.7h of sunshine, December has the least sunshine of the year.UV index
February and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for average individuals.Note: In December, the UV index of 2 transforms into the following advice:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
O'Brien, OR
- Average high temperature in December: 50.4°F
The warmest month (with the highest average high temperature) is July (71.8°F).
The month with the lowest average high temperature is December (50.4°F).
- Average low temperature in December: 40.6°F
The month with the highest average low temperature is July (53.6°F).
The coldest month (with the lowest average low temperature) is February (40.5°F).
Average pressure in December
O'Brien, OR
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (29.99"Hg).
Average wind speed in December
O'Brien, OR
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is March (8.2mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).
Average humidity in December
O'Brien, OR
- Average humidity in December: 80%
The month with the highest relative humidity is March (83%).
The month with the lowest relative humidity is September (72%).
Average rainfall in December
O'Brien, OR
- Average rainfall in December: 7.44"
The wettest month (with the highest rainfall) is January (8.11").
The driest month (with the least rainfall) is July (0.12").
Average rainfall days in December
O'Brien, OR
- Average rainfall days in December: 17 days
The month with the highest number of rainy days is March (19.2 days).
The month with the least rainy days is July (2.3 days).
Average snowfall in December
O'Brien, OR
- Average snowfall in December: 0"
The month with the highest snowfall is February (0.59").
The months with the least snowfall are January, March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in December
O'Brien, OR
- Average snowfall days in December: 0.1 days
The month with the highest number of snowfall days is February (0.3 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in December /
Average sunshine in December
O'Brien, OR
- Average daylight in December: 9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 42min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 4h and 42min).
Average sunshine days in December
O'Brien, OR
- Average sunshine days in December: 13 days
The month with the most sunshine days is July (27.7 days).
The month with the least sunshine days is March (10.5 days).
Average UV index in December
O'Brien, OR
- 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 February and December (UV index 2).
Average cloud cover in December
O'Brien, OR
- Average cloud cover in December: 47
The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 10).
Average visibility in December
O'Brien, OR
- 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).





