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San Francisco weather by month
Historical averages 2016–2025 · not a forecast
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When is the best time to visit San Francisco?
For a warm holiday, the best week has been 13–19 August (Weather Index 95). Favourable start dates for a 7-day trip run from 31 July to 7 September. August and September are warmest (25°C), July is driest and June and July have the most sun.
- Warmest
- August and September 25°C
- Coolest
- January and December 15°C
- Driest
- July 0% rain-day chance
- Wettest
- March 33% rain-day chance
- Sunniest
- June and July 14 hours a day
A rain day has 1 mm or more, snow included, so a short shower counts. Monthly averages below give the amounts.
Monthly averages in San Francisco
San Francisco historical monthly estimates, 2016–2025. Temperatures and sunshine are daily averages.
| Month | High (°C) | Low (°C) | Rain-day chance (%) | Expected rain days | Precipitation (mm/month) | Sunshine (hours/day) |
|---|---|---|---|---|---|---|
| January | 15.0 | 7.6 | 31.9 | 9.9 | 104.3 | 7.1 |
| February | 16.7 | 7.4 | 26.4 | 7.4 | 79.1 | 9.0 |
| March | 17.1 | 8.7 | 33.2 | 10.3 | 85.5 | 9.8 |
| April | 19.5 | 10.0 | 13.0 | 3.9 | 24.5 | 11.5 |
| May | 21.2 | 11.6 | 7.1 | 2.2 | 14.3 | 13.2 |
| June | 23.4 | 13.1 | 1.0 | 0.3 | 1.0 | 13.7 |
| July | 23.7 | 13.6 | 0.0 | 0.0 | 0.0 | 13.7 |
| August | 24.6 | 14.5 | 0.3 | 0.1 | 0.4 | 12.8 |
| September | 25.3 | 14.3 | 0.3 | 0.1 | 2.2 | 11.7 |
| October | 23.5 | 12.1 | 7.7 | 2.4 | 23.6 | 10.0 |
| November | 18.4 | 9.0 | 20.0 | 6.0 | 48.7 | 8.6 |
| December | 14.6 | 7.1 | 29.4 | 9.1 | 93.6 | 7.0 |
Each month averages its own days. Precipitation includes snow. About the data
Sources
Open-Meteo · 1 Jan 2016 – 31 Dec 2025
- Open-Meteo Historical Weather API
- Local days, 2016–2025, every year weighted equally. Each weekly chart averages its own seven days, without smoothing.
- Shading shows the 10th–90th percentile of past days, not forecast confidence.
- A rain day has at least 1 mm, snow included. The last weekly period has eight days.
- Wind is the average daytime (10:00–18:00) maximum, not gusts. Daylight is calculated from latitude. Missing readings stay blank.
- Mugginess (dew point) comes from the original daily summaries, on UTC days.
- The live two-week forecast comes from the Open-Meteo Weather Forecast API. The Weather Index does not use it.