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South San Francisco (CA) Weather and Climate: A Comprehensive Guide

Temperatures in South San Francisco experience a moderate degree of variance through the seasons. Days can be warm, while the cooler months tend to be mild. The city tends toward drier weather patterns. Let's now guide you through the climate details for a complete overview.

Average maximum day and minimum night temperature

In South San Francisco, seasonal changes bring about a moderate variation in temperatures. Typically, average maximum daytime temperatures range from a comfortable 23°C in September to a moderate 14°C in the coolest month, January.

Nights are cooler, with lows often dropping to around 7°C during the colder months. Check out our detailed temperature page for more information.

Temperature ranges by month

Precipitation and rainy days

With annual rainfall averaging 488 mm, South San Francisco maintains relatively low precipitation levels throughout the seasons. The climate in South San Francisco shows significant variation throughout the year. Expect high rainfall in December, with an average of 114 mm of precipitation over 13 rainy days.

In contrast, July offers drier and sunnier days, with around 0.5 mm of rainfall over a single rainy day. For more details, please visit our South San Francisco Precipitation page.

The mean monthly precipitation over the year, including rain, hail and snow

Sunshine over the year

For those who appreciate different seasons, South San Francisco serves as an ideal destination. Expect longer, more sun-filled days in May with an average of 10.8 hours of sunshine daily, and embrace the darker days in December, offering only 5.3 hours of daily sunlight. Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Data from: San Francisco, the United States of America (4 KM, 2 Miles).

Daily hours of sunshine

Data from: San Francisco, the United States of America (4 KM, 2 Miles).

Average water temperature

The mean water temperature over the year ranges from 12°C in January to 14°C in June.

Water temperature over the year

Data from: San Francisco, the United States of America (4 KM, 2 Miles).

Forecast for South San Francisco (CA)

Fri   Dec 27
16°C | 12°C
W 4 m/s
1.6 mm
broken clouds and slight rain

broken clouds and slight rain

Sat   Dec 28
17°C | 12°C
SW 4 m/s
1.1 mm
broken clouds and  chance of slight rain

broken clouds and chance of slight rain

Sun   Dec 29
15°C | 10°C
SW 9 m/s
8.3 mm
broken clouds and rain

broken clouds and rain

The best time of year to visit South San Francisco in the United States of America

During the months of June, July, August, September and October you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.

Other facts from our historical weather data:
  • Does South San Francisco have a dry season?
    Yes, the months of May, June, July, August and September are very dry.
  • Which is the warmest month in South San Francisco?
    September has an average maximum temperature of 23°C and is the warmest month of the year.
  • Which is the coldest month in South San Francisco?
    The coldest month is January with an average maximum temperature of 14°C.
  • Which is the wettest month in South San Francisco?
    December tops the wettest month list with 114 mm of rainfall.
  • Which is the driest month in South San Francisco?
    July is the driest month with 1 mm of precipitation.
  • Which is the sunniest month in South San Francisco?
    May is the sunniest month with an average of 324 hours of sunshine.

  • No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.