High seasons and low seasons, explained.
Mark Twain famously said, “The coldest winter I ever spent was a summer in San Francisco.” Seasons in San Francisco don't necessarily follow universal trends. The city can often feel quite chilly, although the temperature rarely drops below freezing. Even when summer arrives, residents know not to leave the house in short sleeves until late summer—that's when San Francisco enjoys its warmest weather.
Temperatures remain moderate year round: 51 - 65°F (10.5 - 18.3 °C).
Late summer and fall are the most popular times to visit the city: 68 - 70°F (20 - 21°C). The period of warm weather is known as “Indian Summer,” an annual miracle that San Franciscans look forward to all year long. The weather brings favorite festivals and events along with it.
Summers generally range from 53 - 69°F (11.6 - 20.5 °C). Summer days often begin with fog which usually burns off by the afternoon. It rarely rains during summer months.
Winters are mild. They are somewhat wet, but not unbearable: 46 - 48°F ( 7.7 - 8.8 °C).
No matter the season, it is always smart to dress in layers and be prepared for sudden weather changes when in SF.
High Season: SF receives an influx of travelers from May to October. The number of visitors reaches its peak in July and August. Large conventions in September and October bring a high volume of business-minded travelers to the city, so expect crowds in SoMa near the Moscone Center.
Low Season: Temperatures are at their coolest from November to April. The winter months bring fewer hours of daylight and higher chances of rain, making them less popular months with visiting crowds. If you like the feeling of having the city to yourself, this is the time to come to SF.
The Giants: Catch a homerun ball at AT&T Park, March-October.
The 49ers: Cheer on the 49ers at Levi's Stadium, September-January.
The Oakland A's: See them at the Coliseum in Oakland, March-October.
The Oakland Raiders: Get into the (end)zone at the Coliseum, September-January.
The Golden State Warriors: Cheer last-second three pointers at the Oracle Arena in Oakland, October-April.
San Jose Sharks: Heat up the ice at the Shark Tank, October-April.