Climate and monthly weather forecast
South San Francisco, CA

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A sign in large font of the South San Francisco City, California, on the hills over the scenic home setting below
A sign in large font of the South San Francisco City, California, on the hills over the scenic home setting below

Weather in January

January, like December, is a moderate winter month in South San Francisco, California, with an average temperature varying between 47.8°F (8.8°C) and 56.3°F (13.5°C). The weather during January records an average high-temperature of a still moderate 56.3°F (13.5°C), closely mirroring the preceding month. Weather in January »

Weather in February

The last month of the winter, February, is also a moderate month in South San Francisco, California, with an average temperature ranging between max 57.2°F (14°C) and min 47.8°F (8.8°C). February's climate shows a minor adjustment in average high-temperatures to a still moderate 57.2°F (14°C) from January's 56.3°F (13.5°C). Weather in February »

Weather in March

March, the first month of the spring in South San Francisco, is also a moderate month, with an average temperature varying between 48.2°F (9°C) and 58.5°F (14.7°C). The arrival of March is marked by an average high-temperature of a still mild 58.5°F (14.7°C), bearing a close resemblance to February. Weather in March »

Weather in April

April in South San Francisco, California, is a comfortable spring month, with an average temperature ranging between max 61.3°F (16.3°C) and min 49.3°F (9.6°C). South San Francisco records a slight change with April's average high-temperatures adjusting to a still refreshing 61.3°F (16.3°C) from March's 58.5°F (14.7°C). Weather in April »

Weather in May

May, the last month of the spring in South San Francisco, is another refreshing month, with an average temperature ranging between min 51.1°F (10.6°C) and max 63°F (17.2°C). The arrival of May coincides with an average high-temperature of a still refreshing 63°F (17.2°C), indicating a minimal shift from April's 61.3°F (16.3°C). Weather in May »

Weather in June

The first month of the summer, June, is still a refreshing month in South San Francisco, California, with temperature in the range of an average high of 66.9°F (19.4°C) and an average low of 53.6°F (12°C). During June, the average high-temperature is a still refreshing 66.9°F (19.4°C), maintaining a close resemblance to that of the preceding month. Weather in June »

Weather in July

July is a pleasant summer month in South San Francisco, California, with an average temperature varying between 68.9°F (20.5°C) and 54.7°F (12.6°C). The high-temperature average in July for South San Francisco is a pleasant 68.9°F (20.5°C), staying closely aligned with June's conditions. Weather in July »

Weather in August

August, the last month of the summer in South San Francisco, is also an agreeable month, with an average temperature ranging between min 56.5°F (13.6°C) and max 69.1°F (20.6°C). South San Francisco sees the arrival of August with an average high-temperature of a still pleasant 69.1°F (20.6°C), indicating a subtle variation from July. Weather in August »

Weather in September

The first month of the autumn, September, is also an agreeable month in South San Francisco, California, with an average temperature ranging between max 70°F (21.1°C) and min 56.5°F (13.6°C). South San Francisco experiences its highest temperatures in September, with an average peak of 70°F (21.1°C) and a low of 56.5°F (13.6°C). Weather in September »

Weather in October

October, the same as September, is another enjoyable autumn month in South San Francisco, California, with an average temperature varying between 55.4°F (13°C) and 66.9°F (19.4°C). South San Francisco's weather in October, with an average high-temperature of an enjoyable 66.9°F (19.4°C), subtly shifts from September's 70°F (21.1°C). Weather in October »

Weather in November

The last month of the autumn, November, is also an enjoyable month in South San Francisco, California, with an average temperature varying between 61°F (16.1°C) and 51.6°F (10.9°C). A subtle shift in South San Francisco's weather is observed as October turns into November, with the average high temperature reducing from a comfortable 66.9°F (19.4°C) to a still refreshing 61°F (16.1°C). Weather in November »

Weather in December

December, the first month of the winter in South San Francisco, is still a mild month, with an average temperature fluctuating between 55.6°F (13.1°C) and 47.8°F (8.8°C). December is the month when South San Francisco experiences its coldest temperatures, averaging a high of 55.6°F (13.1°C) and a low of 47.8°F (8.8°C). Weather in December »

Frequently asked questions

How much does it rain?

In South San Francisco, during the entire year, the rain falls for 53.6 days and collects up to 3.9" (99mm) of precipitation.

What is the wettest month?

The month with the most rainfall is February, when the rain falls for 6.1 days and typically aggregates up to 0.79" (20mm) of precipitation.

What are the months with the lowest UV index?

The months with the lowest UV index are February and December, with an average maximum UV index of 3.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.

What is the driest month?

June through August are months with the least rain when the rain falls for 1.1 days and typically aggregates up to 0.04" (1mm) of rain.

When are the longest days?

The month with the longest days is June, with an average of 14h and 42min of daylight.

What is the month with the highest UV index?

June through September, with an average maximum UV index of 5, are months with the highest UV index.

What month has the most sunshine?

With an average of 11.7h of sunshine, July has the most sunshine of the year.

What is the most humid month?

August is the most humid month, with an average relative humidity of 78%.

What part of the year is the hottest?

The warmest period is September, when temperatures fluctuate between an average high of 70°F (21.1°C) and a low of 56.5°F (13.6°C).

What are the least humid months in South San Francisco?

The months with the lowest humidity are October and November, with an average relative humidity of 71%.

What are the coldest months?

December, marked by an average high-temperature of 55.6°F (13.1°C) and a low-temperature of 47.8°F (8.8°C), is the coldest month.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 36min of daylight.

What is the month with the least sunshine?

With an average of 5.8h of sunshine, December has the least sunshine of the year.

Average temperature
South San Francisco, CA

Average temperature - South San Francisco, CA

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).

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
South San Francisco, CA

Average pressure - South San Francisco, CA

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
South San Francisco, CA

Average wind speed - South San Francisco, CA

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
South San Francisco, CA

Average humidity - South San Francisco, CA

The month with the highest relative humidity is August (78%).
The months with the lowest relative humidity are October and November (71%).

Average rainfall
South San Francisco, CA

Average rainfall - South San Francisco, CA

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
South San Francisco, CA

Average rainfall days - South San Francisco, CA

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 / Average sunshine
South San Francisco, CA

Average daylight / Average sunshine - South San Francisco, CA

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).

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
South San Francisco, CA

Average sunshine days - South San Francisco, CA

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
South San Francisco, CA

Average UV index - South San Francisco, CA

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 visibility
South San Francisco, CA

Average visibility - South San Francisco, CA

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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