September - November (Fall) - BEST TIME TO VISIT. San Francisco's warmest and sunniest season with temperatures 65-75°F (18-24°C). Minimal fog, clear skies, and fewer tourists after Labor Day. Perfect weather for outdoor activities and neighborhood exploration.
March - May (Spring) - Excellent visiting season with mild temperatures (55-65°F/13-18°C) and blooming flowers in parks and gardens. Some fog begins in late May. Cherry blossoms peak in Japanese Tea Garden late March. Moderate tourist crowds.
December - February (Winter) - San Francisco's rainy season but still mild (50-60°F/10-16°C) with occasional sunny days. Holiday decorations and events make it festive. Lowest hotel rates and smallest crowds except around major holidays. Perfect for museum visits and indoor attractions.
June - August (Summer) - Most popular but FOGGIEST season. Morning fog (known locally as 'Karl the Fog') often blankets western neighborhoods and can last until afternoon. Temperatures surprisingly cool (55-65°F/13-18°C) especially near the coast. Warmest areas are Mission District, South of Market, and eastern neighborhoods. Large tourist crowds and highest prices. Pack layers summer in SF is not beach weather!
| Month | Avg High | Avg Low | Rain Days |
|---|---|---|---|
| January | 57°F/14°C | 46°F/8°C | 11 |
| April | 63°F/17°C | 49°F/9°C | 4 |
| July | 67°F/19°C | 54°F/12°C | 0 |
| October | 70°F/21°C | 54°F/12°C | 3 |
Pro Tip: Mark Twain never actually said "The coldest winter I ever spent was a summer in San Francisco," but the sentiment rings true. Always bring layers!