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
The weather during January records an average high-temperature of a still moderate 56.3°F (13.5°C), closely mirroring the preceding month. In South San Francisco, a slight decrease from the daytime peak is noted during the month of January, with an average low-temperature of 47.8°F (8.8°C).Humidity
In January, the average relative humidity is 73%.Rainfall
In South San Francisco, during January, the rain falls for 7.2 days and regularly aggregates up to 0.51" (13mm) of precipitation. In South San Francisco, during the entire year, the rain falls for 53.6 days and collects up to 3.9" (99mm) of precipitation.Daylight
In South San Francisco, the average length of the day in January is 9h and 55min.On the first day of January, sunrise is at 7:24 am and sunset at 5:01 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 5:31 pm PST.
Sunshine
In South San Francisco, the average sunshine in January is 6h.UV index
In South San Francisco, the average daily maximum UV index in January is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: The daily maximum UV index of 4 in January interprets into the following advice:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average January temperature?
What is the average humidity in January in South San Francisco?
How many days does it rain in January?
How many hours of daylight does South San Francisco have in January?
When are sunrise and sunset in January?
How many hours of sunshine does South San Francisco have in January?
What is the UV index reading in January in South San Francisco?
Average temperature in January
South San Francisco, CA
- Average high temperature in January: 56.3°F
The warmest month (with the highest average high temperature) is September (70°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in January: 47.8°F
The months with the highest average low temperature are August and September (56.5°F).
The coldest months (with the lowest average low temperature) are January, February and December (47.8°F).
Average pressure in January
South San Francisco, 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
South San Francisco, CA
- Average wind speed in January: 6.6mph
The windiest month (with the highest average wind speed) is April (8.5mph).
The calmest month (with the lowest average wind speed) is September (6.2mph).
Average humidity in January
South San Francisco, CA
- Average humidity in January: 73%
The month with the highest relative humidity is August (78%).
The months with the lowest relative humidity are October and November (71%).
Average rainfall in January
South San Francisco, CA
- Average rainfall in January: 0.51"
The wettest month (with the highest rainfall) is February (0.79").
The driest months (with the least rainfall) are June, July and August (0.04").
Average rainfall days in January
South San Francisco, CA
- Average rainfall days in January: 7.2 days
The month with the highest number of rainy days is March (9.4 days).
The month with the least rainy days is June (1.1 days).
Average daylight in January /
Average sunshine in January
South San Francisco, 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 42min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in January
South San Francisco, CA
- Average sunshine days in January: 22.7 days
The months with the most sunshine days are June, July and September (26.3 days).
The month with the least sunshine days is March (19.4 days).
Average UV index in January
South San Francisco, 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 and December (UV index 3).
Average cloud cover in January
South San Francisco, CA
- Average cloud cover in January: 33
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
South San Francisco, 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).
South San Francisco, California, USA
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