South San Francisco Weather in September

During September, South San Francisco experiences high daytime temperatures of 23°C (73°F) and cooler nights around 13°C (55°F). Rainfall is low, averaging just 3.7 mm (0.1 in) for the month.

Rainfall in South San Francisco in September

Typically, you can expect about a single day of rain this month, with 3.7 mm (0.1 in) on average. On the rare occasion it rains this month, it usually amounts to very little.

Temperature in South San Francisco in September

The perfect temperature in South San Francisco in September makes it a solid month to visit, with 23°C (73°F) during the day and 13°C (55°F) at night. This kind of day-to-night contrast is typical for this time of year. With overnight lows of 13°C (55°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep. On average, it has the peak temperatures of the year.

Sunshine in South San Francisco in September

There are approximately 270 hours of sunshine this month, resulting in mostly clear days.

Wind Speed in South San Francisco in September

Average wind conditions reach 5 m/s (10 knots) in September. This creates lively weather with fresh winds that make small trees sway noticeably. Remember this is an average: some days are less windy while others have particularly active windy conditions.

Average water temperature in September

The water temperature is 14°C (57°F) — chilly, but perfectly fine for a swim if you're not too sensitive to cold water. A short wetsuit can make longer sessions more comfortable.

If you favor pleasant temperatures and minimal rainfall, September is one of the best months to visit South San Francisco.

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our South San Francisco's climate page.

South San Francisco Temperature in September

Min Temperature 13°C (55°F)  

Max Temperature 23°C (73°F)  

Water Temperature 14°C (57°F) *  

Chance of Rain 3%  

Precipitation 3.7 mm (0.1 in)  

Rainy days a single day  

Humidity 73% *  

Windspeed 5 m/s (10 knots) *  

Sunshine 270 hours *  

Percentage Sunshine 73% *  

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

What to Wear in South San Francisco in September

Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. With minimal rainfall expected, you can leave the rain gear at home. Expect water temperatures of around 14°C (57°F), which is definitely too cold for comfortable swimming. Your luggage space is better used for other items. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.

What To Do in South San Francisco in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Cycling

10/10

Walking

10/10

Barbeque

9/10

Camping

10/10

Outdoor sports

10/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our South San Francisco's climate page.

More climate data for South San Francisco

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full South San Francisco climate overview or explore weather in the United States of America.