August is one of the warmer months of the year in San Francisco, with average highs near 23.6°C and lows around 12.7°C (mean 18.2°C). It is one of the drier months, averaging 2 mm of rainfall and 72% relative humidity across the period.
August is one of the warmer months of the year in San Francisco. Across 45 years of records, the warmest August in San Francisco was 2020 — when the month averaged 19.5°C — while the coldest were 2010 and 2011 at 16.5°C. Typical August days reach 23.6°C with nights near 12.7°C. The long-term August temperature trend is broadly flat.
August is one of the drier months in San Francisco, averaging 2 mm of rainfall. The wettest August on record was 1997 with 16 mm, while the driest were 1998, 2021 and 2022 at 0 mm.
Relative humidity in San Francisco during August averages 72%. The most humid August was 2011 at 79%, and the least humid was 1981 at 67%.
August receives about 5.9 kWh/m²/day of solar energy in San Francisco. The sunniest Augusts were 2019, 2022 and 2025, among others at 6.4 kWh/m²/day, and the cloudiest was 1986 at 4.4.
Average wind speed in San Francisco during August is 2.3 m/s. The windiest Augusts were 2024 and 2025 at 2.6 m/s, while the calmest were 1989, 1998 and 2005, among others at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 18.1°C | 18.4°C | 17.9°C | 17.8°C | 18.8°C | +0.7°C |
| Avg High | 23.9°C | 24.2°C | 23.3°C | 22.8°C | 24.1°C | +0.2°C |
| Avg Low | 12.3°C | 12.7°C | 12.4°C | 12.8°C | 13.6°C | +1.3°C |
| Avg Rain | 2 mm | 3 mm | 2 mm | 1 mm | 1 mm | -2 mm |
August temperatures in San Francisco have risen by about 0.4°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 9.8°C (1996) to a record high of 35.5°C (2020).
Rainfall in August is one of the drier months, averaging 2 mm, with a wettest year of 16 mm.
Daytime highs and overnight lows have shifted differently — highs fell about 0.2°C per decade while lows rose 0.2°C per decade, narrowing the gap between day and night.
One of the best times to visit San Francisco
August is one of the best times to visit San Francisco. Expect days averaging 23.6°C and nights around 12.7°C (mean 18.2°C) — warmer than San Francisco's yearly average — with low rainfall (2 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 24.2°C | 18.8°C | 13.4°C | 29.9°C | 12.0°C | 1 mm | 72% | 2.6 m/s | 6.4 |
| 2024 | 23.4°C | 18.3°C | 13.2°C | 28.2°C | 12.2°C | 1 mm | 73% | 2.6 m/s | 6.3 |
| 2023 | 24.5°C | 19.3°C | 14.1°C | 31.6°C | 12.3°C | 1 mm | 73% | 2.4 m/s | 5.9 |
| 2022 | 24.0°C | 18.8°C | 13.6°C | 28.9°C | 11.5°C | 0 mm | 72% | 2.4 m/s | 6.4 |
| 2021 | 23.8°C | 18.4°C | 13.0°C | 32.3°C | 10.9°C | 0 mm | 72% | 2.5 m/s | 5.6 |
| 2020 🔥 | 25.0°C | 19.5°C | 14.1°C | 35.5°C | 11.3°C | 1 mm | 68% | 2.4 m/s | 5.6 |
| 2019 | 24.8°C | 19.4°C | 14.0°C | 31.8°C | 12.4°C | 1 mm | 73% | 2.5 m/s | 6.4 |
| 2018 | 22.6°C | 17.5°C | 12.5°C | 27.0°C | 10.8°C | 0 mm | 75% | 2.4 m/s | 5.5 |
| 2017 | 23.5°C | 18.6°C | 13.7°C | 34.0°C | 11.6°C | 1 mm | 74% | 2.4 m/s | 5.3 |
| 2016 | 21.6°C | 16.8°C | 12.0°C | 24.8°C | 10.6°C | 0 mm | 77% | 2.4 m/s | 5.5 |
| 2015 | 23.9°C | 19.1°C | 14.3°C | 31.6°C | 13.0°C | 1 mm | 75% | 2.4 m/s | 6.1 |
| 2014 | 23.4°C | 18.5°C | 13.7°C | 27.7°C | 12.5°C | 0 mm | 76% | 2.2 m/s | 5.4 |
| 2013 | 22.6°C | 17.7°C | 12.8°C | 28.1°C | 11.0°C | 1 mm | 77% | 2.3 m/s | 6.1 |
| 2012 | 22.2°C | 16.9°C | 11.7°C | 26.8°C | 10.0°C | 1 mm | 73% | 2.4 m/s | 5.7 |
| 2011 | 21.4°C | 16.5°C | 11.5°C | 26.4°C | 10.5°C | 1 mm | 79% | 2.3 m/s | 5.7 |
| 2010 ❄️ | 21.7°C | 16.5°C | 11.3°C | 34.6°C | 9.9°C | 1 mm | 76% | 2.3 m/s | 5.6 |
| 2009 | 23.8°C | 18.1°C | 12.5°C | 32.8°C | 10.3°C | 1 mm | 72% | 2.1 m/s | 6.2 |
| 2008 | 24.4°C | 18.6°C | 12.8°C | 35.2°C | 10.3°C | 1 mm | 71% | 2.3 m/s | 6 |
| 2007 | 23.2°C | 17.9°C | 12.6°C | 28.8°C | 10.7°C | 5 mm | 74% | 2.2 m/s | 6.2 |
| 2006 | 22.4°C | 17.1°C | 11.9°C | 31.7°C | 10.8°C | 1 mm | 77% | 2.2 m/s | 5.8 |
| 2005 | 22.6°C | 17.3°C | 12.1°C | 31.0°C | 10.6°C | 1 mm | 75% | 2 m/s | 5.6 |
| 2004 | 24.1°C | 18.7°C | 13.3°C | 31.9°C | 11.9°C | 1 mm | 74% | 2.1 m/s | 5.7 |
| 2003 | 23.5°C | 18.4°C | 13.3°C | 28.8°C | 11.2°C | 4 mm | 75% | 2.1 m/s | 6.4 |
| 2002 | 23.6°C | 17.7°C | 11.9°C | 33.2°C | 10.0°C | 0 mm | 70% | 2.2 m/s | 5.5 |
| 2001 | 22.8°C | 17.4°C | 12.1°C | 27.0°C | 10.8°C | 1 mm | 74% | 2.2 m/s | 6.3 |
| 2000 | 22.7°C | 17.3°C | 11.9°C | 28.1°C | 10.6°C | 4 mm | 72% | 2.1 m/s | 6.2 |
| 1999 | 23.0°C | 17.7°C | 12.5°C | 30.8°C | 11.2°C | 1 mm | 72% | 2.2 m/s | 5.9 |
| 1998 | 25.0°C | 18.9°C | 12.9°C | 32.3°C | 10.9°C | 0 mm | 69% | 2 m/s | 5.7 |
| 1997 🌧️ | 23.9°C | 18.8°C | 13.7°C | 29.9°C | 11.8°C | 16 mm | 74% | 2.3 m/s | 6.4 |
| 1996 | 24.6°C | 18.4°C | 12.2°C | 30.6°C | 9.8°C | 2 mm | 67% | 2.1 m/s | 6.1 |
| 1995 | 23.8°C | 18.0°C | 12.1°C | 30.0°C | 10.1°C | 1 mm | 68% | 2.2 m/s | 6.2 |
| 1994 | 24.5°C | 18.2°C | 11.9°C | 30.7°C | 10.9°C | 1 mm | 69% | 2.2 m/s | 6.3 |
| 1993 | 24.7°C | 18.9°C | 13.2°C | 31.9°C | 11.5°C | 2 mm | 69% | 2.2 m/s | 5.8 |
| 1992 | 24.6°C | 18.7°C | 12.8°C | 28.5°C | 10.7°C | 1 mm | 68% | 2.1 m/s | 5.5 |
| 1991 | 23.0°C | 17.8°C | 12.6°C | 30.7°C | 11.0°C | 5 mm | 76% | 2.2 m/s | 5.6 |
| 1990 | 24.5°C | 19.0°C | 13.5°C | 31.5°C | 11.1°C | 1 mm | 70% | 2.2 m/s | 5.9 |
| 1989 | 23.3°C | 17.5°C | 11.6°C | 30.0°C | 10.1°C | 2 mm | 71% | 2 m/s | 5.8 |
| 1988 | 24.1°C | 18.3°C | 12.4°C | 32.8°C | 11.1°C | 0 mm | 70% | 2.3 m/s | 5.6 |
| 1987 | 24.0°C | 18.1°C | 12.2°C | 28.1°C | 10.7°C | 0 mm | 68% | 2 m/s | 5.4 |
| 1986 | 23.6°C | 17.7°C | 11.9°C | 28.0°C | 10.1°C | 1 mm | 72% | 2 m/s | 4.4 |
| 1985 | 24.0°C | 18.1°C | 12.3°C | 30.4°C | 11.0°C | 1 mm | 67% | 2.3 m/s | 5.9 |
| 1984 | 24.7°C | 18.7°C | 12.7°C | 29.6°C | 11.3°C | 4 mm | 68% | 2.4 m/s | 5.9 |
| 1983 | 23.5°C | 18.5°C | 13.5°C | 28.1°C | 11.7°C | 9 mm | 75% | 2.2 m/s | — |
| 1982 | 23.4°C | 17.9°C | 12.4°C | 29.3°C | 10.5°C | 2 mm | 69% | 2.3 m/s | — |
| 1981 | 24.9°C | 18.5°C | 12.1°C | 30.0°C | 10.7°C | 3 mm | 67% | 2.4 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 23.6°C with lows near 12.7°C (mean 18.2°C), based on 45 years of NASA POWER data.
August averages 2 mm of rainfall in San Francisco, one of the drier months. The wettest on record was 16 mm in 1997.
The hottest August reached 35.5°C in 2020. The coldest dipped to 9.8°C in 1996.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.4°C — but days and nights have moved in opposite directions. Overnight lows rose from 12.6°C to 13.5°C while daytime highs eased from 24.1°C to 24°C, narrowing the gap between day and night.
August is one of the warmer months of the year in San Francisco and one of the drier months, so plan for around 23.6°C daytime highs and 12.7°C at night.
Not quite — August is the 11th coolest month in San Francisco, averaging 18.2°C.
For August in San Francisco, pack light layers you can adjust through the day, with typical highs of 23.6°C and lows of 12.7°C.
Relative humidity in August averages 72% — moderately humid.
Average wind speed in August is 2.3 m/s. The windiest August on record averaged 2.6 m/s (2024).
The wettest August on record was 1997 with 16 mm. On average, August sees 2 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in San Francisco behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
