December weather forecastSan Geronimo, CA
December
Weather in December
December, the first month of the winter in San Geronimo, is also a fresh month, with an average temperature fluctuating between 46°F (7.8°C) and 55.2°F (12.9°C).Temperature
December is the month that records the lowest temperatures, with averages ranging from a high of 55.2°F (12.9°C) to a low of 46°F (7.8°C).Humidity
In San Geronimo, the average relative humidity in December is 73%.Rainfall
In San Geronimo, in December, during 10.9 rainfall days, 2.83" (72mm) of precipitation is typically accumulated. Throughout the year, in San Geronimo, there are 80.3 rainfall days, and 15.98" (406mm) of precipitation is accumulated.Snowfall
The only month with snowfall is December. December has the most snowfall days of the year in San Geronimo. Snow falls for 0.1 days.Daylight
December has the shortest days of the year in San Geronimo, with an average of 9h and 36min of daylight.On the first day of December in San Geronimo, sunrise is at 7:08 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 5:01 pm PST.
Sunshine
The month with the least sunshine in San Geronimo is December, with an average of 5.6h of sunshine.UV index
February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in San Geronimo. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.Note: The UV index of 3 during December leads to these advisories:
Prioritize safety - Recommendations to avert sunburn are shared. Around midday, solar radiation is most harmful; hence, exposure should be limited. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
San Geronimo, CA
- Average high temperature in December: 55.2°F
The warmest month (with the highest average high temperature) is September (70.9°F).
The month with the lowest average high temperature is December (55.2°F).
- Average low temperature in December: 46°F
The month with the highest average low temperature is September (56.3°F).
The coldest month (with the lowest average low temperature) is December (46°F).
Average pressure in December
San Geronimo, CA
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in December
San Geronimo, CA
- Average wind speed in December: 6.7mph
The windiest months (with the highest average wind speed) are April and May (8.3mph).
The calmest month (with the lowest average wind speed) is November (5.9mph).
Average humidity in December
San Geronimo, CA
- Average humidity in December: 73%
The month with the highest relative humidity is August (78%).
The month with the lowest relative humidity is October (69%).
Average rainfall in December
San Geronimo, CA
- Average rainfall in December: 2.83"
The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.08").
Average rainfall days in December
San Geronimo, CA
- Average rainfall days in December: 10.9 days
The month with the highest number of rainy days is March (12.8 days).
The month with the least rainy days is July (2.3 days).
Average snowfall days in December
San Geronimo, CA
- Average snowfall days in December: 0.1 days
The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in December /
Average sunshine in December
San Geronimo, 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: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in December
San Geronimo, CA
- Average sunshine days in December: 18.7 days
The months with the most sunshine days are June and July (24.8 days).
The month with the least sunshine days is March (16.6 days).
Average UV index in December
San Geronimo, CA
- Average UV index in December: 3
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover in December
San Geronimo, CA
- Average cloud cover in December: 37
The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is September (Cloud cover 19).
Average visibility in December
San Geronimo, 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).
