December weather forecastSan Marino, CA
December
Weather in December
The first month of the winter, December, is also an enjoyable month in San Marino, California, with an average temperature ranging between max 63.1°F (17.3°C) and min 47.5°F (8.6°C).Temperature
December, with an average high of 63.1°F (17.3°C) and a low of 47.5°F (8.6°C), signifies the coldest month of the year.Humidity
In December, the average relative humidity is 52%.Rainfall
December is the month with the most rainfall. Rain falls for 4.9 days and accumulates 1.34" (34mm) of precipitation.Daylight
With an average of 9h and 54min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 6:40 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 4:53 pm PST.
Sunshine
The months with the least sunshine are January, February and December, with an average of 6.9h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index of 4 during December translates into these guidelines:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
San Marino, CA
- Average high temperature in December: 63.1°F
The warmest month (with the highest average high temperature) is August (87.1°F).
The month with the lowest average high temperature is December (63.1°F).
- Average low temperature in December: 47.5°F
The month with the highest average low temperature is August (64.8°F).
The coldest month (with the lowest average low temperature) is February (47.1°F).
Average pressure in December
San Marino, CA
- Average pressure in December: 30.08"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in December
San Marino, CA
- Average wind speed in December: 5.2mph
The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in December
San Marino, CA
- Average humidity in December: 52%
The month with the highest relative humidity is June (59%).
The month with the lowest relative humidity is November (47%).
Average rainfall in December
San Marino, CA
- Average rainfall in December: 1.34"
The wettest month (with the highest rainfall) is December (1.34").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
San Marino, CA
- Average rainfall days in December: 4.9 days
The month with the highest number of rainy days is March (5.8 days).
The month with the least rainy days is June (1.2 days).
Average daylight in December /
Average sunshine in December
San Marino, CA
- Average daylight in December: 9h and 54min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in December: 6h and 54min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 54min).
Average sunshine days in December
San Marino, CA
- Average sunshine days in December: 24.5 days
The month with the most sunshine days is June (27.1 days).
The month with the least sunshine days is February (22.3 days).
Average UV index in December
San Marino, CA
- Average UV index in December: 4
The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 4).
Average cloud cover in December
San Marino, CA
- Average cloud cover in December: 21
The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
San Marino, 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).
