Measured, not vibes
Best Time to Visit San Francisco
By measured weather comfort, the top months for San Francisco are August, September, October — and RouteVerdict's editorial pick, which also weighs crowds and prices, is April, May, September, October. The table below is computed from ERA5 reanalysis data for 2020–2024, measured at San Francisco (16 m elevation).
Month by month
San Francisco weather and comfort, 2020–2024
| Month | Avg high | Wet days | Comfort | Season |
|---|---|---|---|---|
| January | 13.9°C / 57°F | 8.8 | 49 | |
| February | 15°C / 59°F | 5.2 | 60 | |
| March | 14.2°C / 58°F | 9.2 | 51 | |
| April | 15.6°C / 60°F | 2.8 | 67 | |
| May | 17.6°C / 64°F | 2.5 | 79 | |
| June | 18.9°C / 66°F | 0.3 | 90 | Shoulder |
| July | 18.7°C / 66°F | 0 | 89 | Shoulder |
| August | 20.3°C / 69°F | 0.2 | 95 | Best |
| September | 20.5°C / 69°F | 0.8 | 95 | Best |
| October | 21°C / 70°F | 2.2 | 93 | Best |
| November | 16.4°C / 62°F | 5.5 | 68 | |
| December | 13.8°C / 57°F | 9.7 | 48 |
Comfort is RouteVerdict's 0–100 score: 100·exp(−(high−23)²/162) × (1 − min(0.35, wet days × 0.02)). The full method is on the methodology page. Weather data by Open-Meteo.com (ERA5, CC BY 4.0), 2020–2024 normals. Wet day = ≥1 mm precipitation.
What the seasons are actually like
Traveling to San Francisco month by month
San Francisco defies the usual summer-is-hottest pattern: June and July are actually cooler than early autumn, with average highs of just 18.9°C and 18.7°C due to coastal fog. Both months still score well on comfort (89.6 and 89.2) because rainfall is nearly zero — 0.3 and 0 wet days. August has the year's top comfort score at 95.2, followed by September's 94.7 and October's 93.3. Winter (December–February) brings the heaviest rain, up to 9.7 wet days in December, and comfort drops to 47.8–60.4. RouteVerdict's editorial pick spans April, May, September, and October — notably skipping August despite its top comfort score.
FAQ
San Francisco timing questions
What is the best month to visit San Francisco?
By measured weather comfort (ERA5 2020–2024), the top months are August, September, and October, with August scoring highest. RouteVerdict's editorial pick is April, May, September, and October, which also weighs crowds, prices, and events.
What is the hottest month in San Francisco?
October, with an average daily high of 21°C (70°F).
What is the rainiest month in San Francisco?
December, averaging 9.7 days with at least 1 mm of precipitation.
When is shoulder season in San Francisco?
June and July — the best-scoring months outside both the measured top three and RouteVerdict's editorial peak-season pick.
Why is summer (June-July) cool in San Francisco?
Coastal fog keeps June and July average highs down to 18.9°C and 18.7°C — genuinely cool for summer — though comfort still scores well (89.6 and 89.2) since rainfall is nearly zero in both months.
Why does San Francisco's editorial pick skip August despite its top comfort score?
August has the year's highest comfort score at 95.2, but RouteVerdict's editorial pick instead centers on April, May, September, and October.