December weather forecastClayton, CA
December
Weather in December
December, the first month of the winter in Clayton, is still a refreshing month, with temperature in the range of an average high of 55.4°F (13°C) and an average low of 41.9°F (5.5°C).Temperature
Clayton's coldest month, December, registers temperatures that range from a high of 55.4°F (13°C) to a low of 41.9°F (5.5°C).Humidity
In Clayton, California, the average relative humidity in December is 71%.Rainfall
In Clayton, during December, the rain falls for 7.5 days and regularly aggregates up to 0.75" (19mm) of precipitation. Throughout the year, in Clayton, there are 50 rainfall days, and 4.76" (121mm) 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 7:05 am and sunset at 4:48 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:58 pm PST.
Sunshine
The month with the least sunshine in Clayton is December, with an average of 5.8h of sunshine.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 reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: A maximum high UV index of 3 in December translates into the following recommendations:
Undertake precautions - Guarding against sun damage is counselled. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Clayton, CA
- Average high temperature in December: 55.4°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is December (55.4°F).
- Average low temperature in December: 41.9°F
The month with the highest average low temperature is September (57.6°F).
The coldest month (with the lowest average low temperature) is January (41.7°F).
Average pressure in December
Clayton, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Clayton, CA
- Average wind speed in December: 4.8mph
The windiest month (with the highest average wind speed) is May (7.4mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in December
Clayton, CA
- Average humidity in December: 71%
The months with the highest relative humidity are January and March (73%).
The months with the lowest relative humidity are September and October (55%).
Average rainfall in December
Clayton, CA
- Average rainfall in December: 0.75"
The wettest month (with the highest rainfall) is February (0.98").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Clayton, CA
- Average rainfall days in December: 7.5 days
The month with the highest number of rainy days is March (8.6 days).
The month with the least rainy days is August (0.8 days).
Average daylight in December /
Average sunshine in December
Clayton, 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 48min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in December
Clayton, CA
- Average sunshine days in December: 22.6 days
The month with the most sunshine days is August (29.4 days).
The month with the least sunshine days is March (21.7 days).
Average UV index in December
Clayton, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Clayton, CA
- Average cloud cover in December: 35
The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in December
Clayton, 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).
