Weather in San Francisco in October

Prime time. October is about as good as San Francisco gets. Highs average 22.6 °C, lows 12.2 °C, and rain falls on 4 days — nothing in the month is working against you.

October ranks 6 of 12 in San Francisco: past the worst of the year but short of July, which is the month to book if the dates are open.

Rain falls on only 4 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest October day reached 34.8 °C and the coldest night fell to 6.2 °C, and the wettest single day dropped 85 mm — roughly 293% of the month's rain in one day.

This is the volatile part. October rainfall has ranged from 0 mm to 102 mm across the twenty years measured — a 102 mm spread around an average of 29 mm. The average is real but almost no individual October looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 6.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.

How October sits in the year

The month is on the way down: 1.9 °C cooler than September, with November dropping another 4.8 °C. The first week and the last are not the same trip.

Daylight in October

11.3 hours of daylight, losing 1.2 hours across the month. That is between San Francisco's extremes of 14.8 and 9.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 15 °C in October — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. This is the warmest the water gets all year.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

October in San Francisco versus nearby

If San Francisco is one option among several, the nearby comparison is worth making. Napa is close enough to be a coin toss — 4.4 °C warmer, 1 day less rain. San Jose is close enough to be a coin toss — 4 °C warmer, 1 day less rain.

So: October works, with July the better month by 8 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in San Francisco

See all twelve months in San Francisco, or where else to go in October.