North America › United States › San Francisco
30-year normals (1991-2020)
San Francisco has a Mediterranean climate, classified as Csb in the Köppen system. The warmest month is September with an average high of 23°C, while the coldest month is January with lows dropping to 7°C. The annual temperature range of 16°C reflects moderate seasonal variation.
The driest month is September with only 0 rain days and 2mm of precipitation. For travellers, September through to the following month typically offers the best balance of warm temperatures and dry conditions. Average humidity ranges from 65% to 65% throughout the year.
Based on temperature and rainfall data, the best months to visit San Francisco are April, May, June. These months offer the most comfortable temperatures with relatively low rainfall, ideal for sightseeing and outdoor activities.
Full Best Time to Visit GuideWarmest Month
23°C
September
Coldest Month
7°C
January
Driest Month
0 days
September
Annual Range
16°C
7° to 23°
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 14°C | 7°C | 10 | 7h | View |
| February | 15°C | 7°C | 9 | 8h | View |
| March | 16°C | 8°C | 9 | 10h | View |
| April | 17°C | 9°C | 5 | 11h | View |
| May | 19°C | 11°C | 3 | 13h | View |
| June | 21°C | 12°C | 1 | 13h | View |
| July | 21°C | 13°C | 0 | 14h | View |
| August | 22°C | 13°C | 0 | 13h | View |
| September | 23°C | 13°C | 0 | 12h | View |
| October | 21°C | 12°C | 3 | 10h | View |
| November | 17°C | 9°C | 6 | 8h | View |
| December | 14°C | 7°C | 9 | 7h | View |
January
10 rain days, 7h sun
February
9 rain days, 8h sun
March
9 rain days, 10h sun
April
5 rain days, 11h sun
May
3 rain days, 13h sun
June
1 rain days, 13h sun
July
0 rain days, 14h sun
August
0 rain days, 13h sun
September
0 rain days, 12h sun
October
3 rain days, 10h sun
November
6 rain days, 8h sun
December
9 rain days, 7h sun
San Francisco in September
Data Sources for San Francisco
Climate normals represent 30-year averages (1991-2020). Individual years may vary.