Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
As San Bruno steps into January, the average high-temperature holds at a still moderate 56.3°F (13.5°C), hinting at a minor fluctuation from the prior month. San Bruno maintains an average low-temperature of 47.8°F (8.8°C) throughout January's nights.Humidity
In San Bruno, the average relative humidity in January is 73%.Rainfall
In San Bruno, in January, it is raining for 10.8 days, with typically 2.2" (56mm) of accumulated precipitation. Throughout the year, there are 81.8 rainfall days, and 13.46" (342mm) of precipitation is accumulated.Daylight
The average length of the day in January is 9h and 55min.On the first day of the month, sunrise is at 7:24 am and sunset at 5:01 pm. On the last day of January, sunrise is at 7:14 am and sunset at 5:31 pm PST.
Sunshine
In San Bruno, the average sunshine in January is 6h.UV index
The average daily maximum UV index in January is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: The maximum UV index of 4 during January leads to these instructions:
Be vigilant - Preventing sunburn is recommended. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. During bright days, sunglasses that offer UVA and UVB defense are recommended.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in January?
What is the average humidity in January?
How much does it rain in January?
What is the average length of the day in January?
When are sunrise and sunset in January?
How many hours of sunshine does San Bruno have in January?
What is the UV index intensity in January?
Average temperature in January
San Bruno, CA
- Average high temperature in January: 56.3°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 January: 47.8°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 January
San Bruno, CA
- Average pressure in January: 30.13"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 January
San Bruno, CA
- Average wind speed in January: 6.7mph
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 January
San Bruno, CA
- Average humidity in January: 73%
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 January
San Bruno, CA
- Average rainfall in January: 2.2"
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 January
San Bruno, CA
- Average rainfall days in January: 10.8 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 January /
Average sunshine in January
San Bruno, CA
- Average daylight in January: 9h and 5min
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 January: 6h and 0min
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 January
San Bruno, CA
- Average sunshine days in January: 19.8 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 January
San Bruno, CA
- Average UV index in January: 4
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 January
San Bruno, CA
- Average cloud cover in January: 34
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 January
San Bruno, CA
- Average visibility in January: 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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