Best time to visit San Francisco

San Francisco is a city of two halves. July scores 100 and December scores 54 — a 46-point swing, which is the difference between a holiday and an endurance test. The month you pick matters more here than almost anywhere. The good window runs May to October — 6 months within ten points of the best.

September is the warmest month at 24.5 °C and January the coolest at 13.9 °C — a 10.6 °C spread across the year.

There is a real wet season here. January, February, March and December carry the rain — up to 12 wet days in a month — while June to September drop as low as 0. That 12-day gap is the biggest single difference between a good month and a bad one in San Francisco, and it moves further than the temperature does.

The sea peaks at just 15.7 °C, which is wetsuit territory even at its warmest — a coast to look at rather than swim in. Daylight runs from 9.6 hours in winter to 14.8 in summer, enough to notice on a sightseeing itinerary.

The three strongest months are July, August, June. The one to think twice about is December. Each month below has its own page with rainfall reliability, extremes, daylight, sea temperature and crowd levels.

San Francisco month by month