| Month | Avg High | Avg Low | Rain days | Verdict |
|---|---|---|---|---|
| Jan | 57°F (14°C) | 46°F (8°C) | 11 | Quiet. Good deals. Bring raincoat. |
| Feb | 60°F (16°C) | 48°F (9°C) | 11 | Same as Jan. Almond blossoms begin. Chinatown New Year parade. |
| Mar | 62°F (17°C) | 49°F (9°C) | 10 | Transitional. Some sunny days. Fewer tourists. |
| Apr | 63°F (17°C) | 50°F (10°C) | 6 | Green hills. Wildflowers. Good walking weather. |
| May | 64°F (18°C) | 51°F (11°C) | 3 | Good month. Before summer fog sets in. Bay to Breakers race. |
| Jun | 66°F (19°C) | 53°F (12°C) | 1 | Fog begins. "June Gloom." Pride weekend is huge. |
| Jul | 66°F (19°C) | 54°F (12°C) | 0 | Peak fog. Coldest-feeling month. Tourists in shorts, freezing. |
| Aug | 68°F (20°C) | 55°F (13°C) | 0 | Foggy mornings, sunny afternoons. Outside Lands festival. |
| Sep | 71°F (22°C) | 56°F (13°C) | 1 | Best month. Warmest. Clearest skies. Fewer tourists. |
| Oct | 70°F (21°C) | 54°F (12°C) | 3 | Second-best. Fleet Week. Blue Angels. Warm days. |
| Nov | 64°F (18°C) | 50°F (10°C) | 8 | Rain returns. Quiet. Good hotel prices. |
| Dec | 57°F (14°C) | 46°F (8°C) | 11 | Holiday lights. Union Square ice rink. Wet but festive. |
The fog machine — why SF summers are cold
San Francisco sits between the cold Pacific Ocean and the hot Central Valley. In summer, hot air rising in the valley pulls cold ocean air and fog through the Golden Gate. This is why the western half of the city (Richmond, Sunset) is foggy all summer while the eastern half (Mission, Potrero) can be 15°F warmer. The phenomenon is called the marine layer. It is the reason the Golden Gate Bridge is painted orange — visibility, not aesthetics.
Best months: September and October
September is statistically the warmest month. The fog retreats. The skies are clear. The tourists have gone home. October is almost as good, plus Fleet Week (Blue Angels air show over the Bay, first weekend of October). Both months have almost no rain.
What to pack — any month
A jacket. Always. The temperature can drop 20°F between noon and 6pm, any day of the year. Layers — a t-shirt, a sweater, and a windproof outer layer — work better than one heavy coat. The wind on the bridge can hit 30mph even in August.
The microclimate cheat sheet
Check the weather for the neighborhood you are going to, not "San Francisco." The Mission can be 75°F and sunny while the Sunset is 58°F and foggy — on the same afternoon, 4 miles apart. Twin Peaks is usually 10°F colder than the Mission. The Golden Gate Bridge is windier than anywhere else. Our audio guides mention what to wear at each stop.
Walk the city in any weather — with a guide
Audio guides for 18 SF stops. Rain or fog, the stories hold up. Free 60-second previews.