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San Francisco in August: Weather, Average temperature and Climate

Discover the weather for San Francisco in August and if it’s a good time to travel (based on historical data).
Check flight prices to San Francisco on Avionero:
August

Weather in San Francisco in August 2025

Good Weather
Warm
☁️
Cloudy
🌊
Cold water
Weather for San Francisco in August is typically good with an average maximum temperature of +24°C during the day, and approximately 6 sunny days monthly. Typically, there are about 0 rainy days with the total average precipitation that falls in August around 1 mm. Expect good weather and pack accordingly to enjoy the outdoors. Search flights in one click on Avionero.
Good to know:
  • August is usually the wettest month of the year in San Francisco;

Average weather

☀️
+24°C
Avg. max. temperature
+10°C
Min.
+34°C
Max.
1 mm
Total precipitation
83%
Avg. humidity
2 m/s
Avg. wind
6 ☀️
Sunny Days
24 ⛅️
Cloudy
0 🌦
Rainy
Our opinion: San Francisco has good weather in August.

Average temperature in San Francisco in August

Here are the expected maximum, average and minimum temperatures in San Francisco for August based on the historical data.
Last Year
Historical Data

The expected average maximum temperature in August is +25°C with a maximum of +30°C and a minimum of +14°C.

The average maximum temperature goes up 50% by the end of the month, compared with the beginning of the month, from +22°C to +30°C.

Is San Francisco warm or cold in August?

San Francisco is typically warm in August.

Maximum temperatures go up compared to the previous month from +23°C to +24°C. The minimum temperature also goes up from +13°C to +14°C.

It’s generally warm, but pack a long-sleeve shirt for evenings.

August is one of the warmest months in San Francisco, here is the comparison with other months:

Water temperature in San Francisco in August

Water in San Francisco in August is Cold. It varies from +12°C to +15°C, with an average of +13°C. The air temperature averaging +24°C is higher than the water temperature.

The water temperature in August is one of the warmest of the entire year:

The warmest water temperatures in San Francisco are reached in September, when the average sea temperature rises to +14°C. The coldest water temperatures are in June, with an average of +11°C.

Can you swim in San Francisco in August?

We would not recommend swimming in San Francisco in August, the water is very cold (+13°C on average). Consider swimming only if you are an experienced cold-water swimmer with proper gear.
🦭
Cold
Below +16°C
🏄‍♂️
Fresh
16°C - 21°C
🏊
Comfortable
21°C - 25°C
👙
Warm
25°C - 28°C
🔥
Very warm
+28°C and up
You will need a full-body wetsuit, cap, gloves, a warm change of clothes, and a hot drink ready for after your swim.

Climate in San Francisco in August

San Francisco weather looks like this, on average, in August and the surrounding months.
JulyAugustSeptember
Avg. temperature
+23°C+24°C+24°C
Min. temperature
+10°C+10°C+9°C
Max. temperature
+35°C+34°C+37°C
Rainfall
0 mm1 mm4 mm
Wind
3 m/s2 m/s2 m/s
Avg. water temperature
+13°C+13°C+14°C
Humidity
82%83%81%
Air pressure
1013 HPa1013 HPa1012 HPa
Sunny days
769
Cloudy days
232419
Rainy days
002
Snowy days
000

August weather is still as good as in July. It’s getting warmer as August arrives. The average maximum temperature goes up from +23°C to +24°C during the day. Prepare for more rain. Average rainfall goes from 0 mm to 1 mm. Humidity rises from 82% to 83%. Winds are calmer in comparison to July, going down from 3 m/s to 2 m/s on average. The days becoming less sunny, going from 7 sunny days in July to 6 in August.

September brings much the same weather, it remains good.

Wind

Wind speed in San Francisco in August based on historical data.
Last Year
Historical Data

The average wind speed is 1 m/s getting up to 2 m/s which is a light breeze; barely moving the tree leaves.

The average wind speed in San Francisco is gradually increasing during August, going from 1 m/s to 2 m/s over the course of the month.

Rain

Amount of rainfall in mm during August in San Francisco based on historical data.
Last Year
Historical Data
Total precipitation in August is about 2 mm, with a 3% chance of rain on a typical day. The maximum amount of rainfall per day is around 2 mm, which is considered light rain. San Francisco is amazing in August with as little as 1 rainy days on average, so plan adventures in the great outdoors.
Here’s how August is compared with other months in the amount of precipitation, total mm:
San Francisco wettest month is December, where a typical day has a 39% chance of precipitation and 117 mm of rainfall per day. July, on the other hand, is the driest month with a mere 0% chance of precipitation and 0 mm of rainfall per day.

How was the weather last August in San Francisco?

This is the weather in San Francisco in August 2023:
1 August
☁️
+22°C
2 August
☁️
+20°C
3 August
☀️
+19°C
4 August
☁️
+22°C
5 August
☀️
+25°C
6 August
☀️
+29°C
7 August
☀️
+28°C
8 August
☁️
+24°C
9 August
☁️
+21°C
10 August
☁️
+21°C
11 August
☁️
+22°C
12 August
☁️
+23°C
13 August
☁️
+24°C
14 August
☁️
+23°C
15 August
☁️
+25°C
16 August
☁️
+23°C
17 August
☁️
+23°C
18 August
☁️
+23°C
19 August
☁️
+22°C
20 August
☁️
+29°C
21 August
☁️
+28°C
22 August
☁️
+25°C
23 August
☀️
+30°C
24 August
☀️
+29°C
25 August
☁️
+22°C
26 August
☁️
+23°C
27 August
☀️
+24°C
28 August
☀️
+26°C
29 August
☀️
+27°C
30 August
☀️
+30°C
31 August
☀️
+30°C
In August 2023 San Francisco had 11 sunny days, 20 cloudy days, and 0 rainy days. The average maximum temperature was +25°C, with an absolute maximum of +30°C and a minimum of +19°C. The average humidity was 84%, with a maximum of 99% and a minimum of 55%. The average wind speed was 1 m/s, with a maximum of 7 m/s and a minimum of 0 m/s.
Are you planning a trip in August?

Climate Change over Years

This is how San Francisco climate have been changing during last 43 years period.

The climate in San Francisco in August has not changed much over the last 43 years.

The average temperature was the lowest in 1982 (+18°C) and the highest in 2014 (+21°C). The driest year was 2013 with only 127 mm of rainfall, and the wettest year was 1983 with 1162 mm.

FAQ

Frequently asked questions about the weather in San Francisco in August:

Is August a good time to visit San Francisco?

August is a really good time to go to San Francisco. The weather is nice so plan your packing around outdoor activities and exploring. Check out other good time to visit San Francisco.

Can you sunbathe in San Francisco in August?

August is warm in San Francisco. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.

Can you swim in San Francisco in August?

Swimming in San Francisco in August is challenging and not recommended for inexperienced swimmers or without proper equipment and preparation.

Is San Francisco rainy in August?

San Francisco is usually dry in August. Plan your packing around outdoor activities and exploring.

Is it sunny in San Francisco in August?

Usually, it’s not very sunny in San Francisco in August, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.

Other cities in USA

Check out the weather for other cities in USA.

Monthly weather in San Francisco

Source of the data

For this page, we’ve looked at the typical weather in San Francisco, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.