Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
December is San Bruno's coldest month, registering average high temperatures of 55.8°F (13.2°C) and lows of 47.7°F (8.7°C).Humidity
The average relative humidity in December is 72%.Rainfall
In San Bruno, in December, it is raining for 11 days, with typically 2.28" (58mm) of accumulated precipitation. Throughout the year, in San Bruno, there are 81.8 rainfall days, and 13.46" (342mm) of precipitation is accumulated.Daylight
December has the shortest days of the year in San Bruno, with an average of 9h and 36min of daylight.On the first day of December, sunrise is at 7:06 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 5:01 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 5.8h of sunshine.UV index
The months with the lowest UV index are February, November and December, with an average maximum UV index of 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 3 in December interprets into the following recommendations:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Frequently asked questions
What time of the year is the coldest in San Bruno?
What is the average December temperature in San Bruno?
What is the average humidity in December in San Bruno?
How much does it rain in San Bruno in December?
What is the month with the shortest days in San Bruno?
How many hours of daylight does San Bruno have in December?
What time are sunrise and sunset in December in San Bruno?
What is the month with the least sunshine in San Bruno?
How long on average sun shines in December in San Bruno?
When is the lowest UV index in San Bruno?
What is the UV index intensity in December in San Bruno?
Average temperature in December
San Bruno, CA
- Average high temperature in December: 55.8°F
The warmest month (with the highest average high temperature) is September (69.8°F).
The month with the lowest average high temperature is December (55.8°F).
- Average low temperature in December: 47.7°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 (47.7°F).
Average pressure in December
San Bruno, 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 September (29.92"Hg).
Average wind speed in December
San Bruno, CA
- Average wind speed in December: 7.4mph
The windiest month (with the highest average wind speed) is April (8.5mph).
The calmest months (with the lowest average wind speed) are August and September (6.3mph).
Average humidity in December
San Bruno, CA
- Average humidity in December: 72%
The month with the highest relative humidity is August (79%).
The months with the lowest relative humidity are October and November (71%).
Average rainfall in December
San Bruno, CA
- Average rainfall in December: 2.28"
The wettest month (with the highest rainfall) is February (2.72").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
San Bruno, CA
- Average rainfall days in December: 11 days
The month with the highest number of rainy days is March (13.3 days).
The months with the least rainy days are July and August (2.2 days).
Average daylight in December /
Average sunshine in December
San Bruno, CA
- Average daylight in December: 9h and 4min
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 5min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in December
San Bruno, CA
- Average sunshine days in December: 19.1 days
The month with the most sunshine days is July (27.3 days).
The month with the least sunshine days is March (16.3 days).
Average UV index in December
San Bruno, 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 Bruno, CA
- Average cloud cover in December: 35
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is September (Cloud cover 16).
Average visibility in December
San Bruno, 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).
San Bruno, California, USA
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