December weather forecastSonoma, CA
December
Weather in December
December denotes the transition into winter with colder temperatures and a noticeable dip in daylight hours to just 9.5 hours daily. The weather takes a decidedly chilly turn, with both high and low temperatures dropping from November. Cloud coverage increases, signalling the heightened possibility of rainfall, which peaks again after a pronounced dry spell. Despite the cooler ambiance, winter sunshine is still a fixture of Sonoma's December weather. Amidst the increasing chill of the cold season, December still manages to end the year on a pleasant note.Temperature
December, marked by an average high-temperature of 55°F (12.8°C) and a low-temperature of 41.4°F (5.2°C), is the coldest month.Humidity
In December, the average relative humidity is 73%.Rainfall
In Sonoma, during December, the rain falls for 10.6 days and regularly aggregates up to 2.72" (69mm) of precipitation. Throughout the year, there are 73.3 rainfall days, and 15.47" (393mm) of precipitation is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:08 am and sunset at 4:49 pm. On the last day of December, sunrise is at 7:26 am and sunset at 4:59 pm PST.
Sunshine
With an average of 5.6h of sunshine, December has the least sunshine of the year.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: In December, the maximum UV index of 3 transforms into these recommendations:
Make use of precautions - It is urged to ward off sun damage. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Sonoma, CA
- Average high temperature in December: 55°F
The warmest month (with the highest average high temperature) is August (82.9°F).
The month with the lowest average high temperature is December (55°F).
- Average low temperature in December: 41.4°F
The month with the highest average low temperature is August (54.9°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).
Average pressure in December
Sonoma, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Sonoma, CA
- Average wind speed in December: 4.8mph
The windiest month (with the highest average wind speed) is May (6.2mph).
The calmest month (with the lowest average wind speed) is November (4.4mph).
Average humidity in December
Sonoma, CA
- Average humidity in December: 73%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (59%).
Average rainfall in December
Sonoma, CA
- Average rainfall in December: 2.72"
The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Sonoma, CA
- Average rainfall days in December: 10.6 days
The month with the highest number of rainy days is March (13.4 days).
The month with the least rainy days is August (0.8 days).
Average daylight in December /
Average sunshine in December
Sonoma, CA
- Average daylight in December: 9h and 36min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 36min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in December
Sonoma, CA
- Average sunshine days in December: 19.4 days
The month with the most sunshine days is July (28.7 days).
The month with the least sunshine days is March (16.1 days).
Average UV index in December
Sonoma, CA
- Average UV index in December: 3
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Sonoma, CA
- Average cloud cover in December: 38
The month with the most cloud cover is March (Cloud cover 40).
The month with the least cloud cover is July (Cloud cover 8).
Average visibility in December
Sonoma, CA
- 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).
