December weather forecastSan Ramon, CA
December
Weather in December
The first month of the winter, December, is also a moderate month in San Ramon, California, with temperature in the range of an average high of 55.9°F (13.3°C) and an average low of 42.1°F (5.6°C).Temperature
San Ramon records the coldest temperatures in December, averaging a high of 55.9°F (13.3°C) and a low of 42.1°F (5.6°C).Humidity
The average relative humidity in December in San Ramon is 71%.Rainfall
In San Ramon, during December, the rain falls for 10 days and regularly aggregates up to 1.73" (44mm) of precipitation. Throughout the year, there are 67.2 rainfall days, and 10.98" (279mm) of precipitation is accumulated.Daylight
The month with the shortest days is December, 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 4:49 pm. On the last day of December, in San Ramon, sunrise is at 7:23 am and sunset at 4:59 pm PST.
Sunshine
December has the least sunshine of the year in San Ramon, with an average of 5.8h of sunshine.UV index
The months with the lowest UV index in San Ramon are January, February, November and December, with an average maximum UV index of 3. 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: The maximum UV index of 3 during December leads to these instructions:
Make use of precautions - It is urged to ward off sun damage. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
San Ramon, CA
- Average high temperature in December: 55.9°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in December: 42.1°F
The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is December (42.1°F).
Average pressure in December
San Ramon, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in December
San Ramon, CA
- Average wind speed in December: 4.7mph
The windiest month (with the highest average wind speed) is May (6.7mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).
Average humidity in December
San Ramon, CA
- Average humidity in December: 71%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).
Average rainfall in December
San Ramon, CA
- Average rainfall in December: 1.73"
The wettest month (with the highest rainfall) is February (2.28").
The driest month (with the least rainfall) is July (0").
Average rainfall days in December
San Ramon, CA
- Average rainfall days in December: 10 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.6 days).
Average daylight in December /
Average sunshine in December
San Ramon, CA
- Average daylight in December: 9h and 36min
The month with the longest days is June (Average daylight: 14h and 42min).
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
San Ramon, CA
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is July (29.9 days).
The month with the least sunshine days is March (17.5 days).
Average UV index in December
San Ramon, 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
San Ramon, 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
San Ramon, 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).
