Monthly weather forecast and climate
South San Francisco, CA

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, the same as December, in South San Francisco, California, is another mild winter month, with temperature in the range of an average high of 56.3°F (13.5°C) and an average low of 47.8°F (8.8°C). In South San Francisco, California, the average high-temperature in January is almost the same as in December - a still moderate 56.3°F (13.5°C). Weather in January »

Weather in February

The last month of the winter, February, is another mild month in South San Francisco, California, with average temperature varying between 57.2°F (14°C) and 47.8°F (8.8°C). In February, the average high-temperature is practically the same as in January - a still mild 57.2°F (14°C). Weather in February »

Weather in March

The first month of the spring, March, is also a moderate month in South San Francisco, California, with average temperature varying between 58.5°F (14.7°C) and 48.2°F (9°C). In March, the average high-temperature is practically the same as in February - a still mild 58.5°F (14.7°C). Weather in March »

Weather in April

April in South San Francisco, California, is a comfortable spring month, with average temperature fluctuating between 49.3°F (9.6°C) and 61.3°F (16.3°C). In South San Francisco, California, the average high-temperature is practically the same as in March - a comfortable 61.3°F (16.3°C). Weather in April »

Weather in May

May, the last month of the spring, in South San Francisco, is also an enjoyable month, with average temperature fluctuating between 51.1°F (10.6°C) and 63°F (17.2°C). In South San Francisco, the average high-temperature in May is almost the same as in April - a still enjoyable 63°F (17.2°C). Weather in May »

Weather in June

The first month of the summer, June, is also an enjoyable 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). In June, the average high-temperature is almost the same as in May - a still enjoyable 66.9°F (19.4°C). Weather in June »

Weather in July

July in South San Francisco, California, is an agreeable summer month, with average temperature varying between 68.9°F (20.5°C) and 54.7°F (12.6°C). In July, the average high-temperature is practically the same as in June - an agreeable 68.9°F (20.5°C). Weather in July »

Weather in August

The last month of the summer, August, is also an agreeable month in South San Francisco, California, with average temperature fluctuating between 69.1°F (20.6°C) and 56.5°F (13.6°C). In August, the average high-temperature is practically the same as in July - a still pleasant 69.1°F (20.6°C). Weather in August »

Weather in September

The first month of the autumn, September, is also an agreeable month in South San Francisco, California, with average temperature fluctuating between 70°F (21.1°C) and 56.5°F (13.6°C). September is the warmest month, with an average high-temperature of 70°F (21.1°C) and an average low-temperature of 56.5°F (13.6°C). Weather in September »

Weather in October

October, like September, in South San Francisco, California, is another enjoyable autumn month, with average temperature fluctuating between 66.9°F (19.4°C) and 55.4°F (13°C). In October, the average high-temperature is essentially the same as in September - an enjoyable 66.9°F (19.4°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 average temperature fluctuating between 61°F (16.1°C) and 51.6°F (10.9°C). In South San Francisco, California, the average high-temperature in November marginally drops, from an enjoyable 66.9°F (19.4°C) in October, to a still comfortable 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 temperature in the range of an average low of 47.8°F (8.8°C) and an average high of 55.6°F (13.1°C). The coldest month is December, with an average high-temperature of 55.6°F (13.1°C) and an average low-temperature of 47.8°F (8.8°C). Weather in December »
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FAQ

How much does it rain in South San Francisco?

Throughout the year, there are 53.6 rainfall days, and 3.9" (99mm) of precipitation is accumulated.

What is the wettest month in South San Francisco?

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 in South San Francisco?

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

What is the driest month in South San Francisco?

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

When are the longest days in South San Francisco?

The month with the longest days in South San Francisco is June, with an average of 14.7h of daylight.

What are the months with the highest UV index in South San Francisco?

June through September, with an average maximum UV index of 5, are months with the highest UV index in South San Francisco, California.

What month has the most sunshine in South San Francisco?

The month with the most sunshine in South San Francisco, California, is July, with an average of 11.7h of sunshine.

What is the most humid month in South San Francisco?

With an average relative humidity of 78%, August is the most humid month in South San Francisco.

What is the warmest month in South San Francisco?

The warmest month is September, with an average high-temperature of 70°F (21.1°C) and an average low-temperature of 56.5°F (13.6°C).

What are the least humid months in South San Francisco?

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

What is the coldest month in South San Francisco?

December is the coldest month in South San Francisco, with an average high-temperature of 55.6°F (13.1°C) and an average low-temperature of 47.8°F (8.8°C).

What is the month with the shortest days in South San Francisco?

December has the shortest days of the year in South San Francisco, California, with an average of 9.6h of daylight.

What is the month with the least sunshine in South San Francisco?

December has the least sunshine of the year in South San Francisco, with an average of 5.8h of sunshine.

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).

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).

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Average pressure
South San Francisco, CA

Average pressure - South San Francisco, CA

The month with the highest atmospheric pressure is January (30.13").
The month with the lowest atmospheric pressure is September (29.92").

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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).

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Average humidity
South San Francisco, CA

Average humidity - South San Francisco, CA

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

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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").

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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).

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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: 14.7h).
The month with the shortest days is December (Average daylight: 9.6h).

The month with the most sunshine is July (Average sunshine: 11.7h).
The month with the least sunshine is December (Average sunshine: 5.8h).

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Average sunshine days
South San Francisco, CA

Average sunshine days - South San Francisco, CA

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).

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Average UV index
South San Francisco, CA

Average UV index - South San Francisco, CA

Months with the highest UV index are June, July, August and September (UV index 5).
Months with the lowest UV index are February and December (UV index 3).

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Average visibility
South San Francisco, CA

Average visibility - South San Francisco, CA

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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