Weather in San Francisco in March

A good month. March is a solid month to be in San Francisco. Highs average 16.3 °C, lows 8.4 °C, and rain falls on 10 days — nothing in the month is working against you.

March ranks 9 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 on 10 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 16.3 °C days and 8.4 °C nights; the spread matters more here than any single number.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest March day reached 25.1 °C and the coldest night fell to 1.8 °C, and the wettest single day dropped 42 mm — roughly 51% of the month's rain in one day.

March is moderately variable: 6 mm in the driest year against 205 mm in the wettest, around an average of 82 mm. Roughly two Marchs in three land near that average, and the third does something else entirely.

Wind is light at 8.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, high enough to notice on the warm days without dominating them.

How March sits in the year

Temperatures hold steady either side: 14.9 °C in February, 16.3 here, 17.4 in April. Nothing about the timing within the month matters much.

Daylight in March

11.9 hours of daylight, gaining 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 12.4 °C in March — too cold to swim without a wetsuit. The sea peaks at 15.7 °C in September and bottoms out at 12.2 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

March 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 — within a degree on temperature, the same number of rain days. San Jose is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: March is a compromise. July is 32 points better and is what San Francisco is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in San Francisco

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