Weather in San Diego in March

Prime time. If you get to pick your dates, March is the one. Highs average 22.1 °C, lows 12 °C, and rain falls on 5 days — nothing in the month is working against you.

March ranks 7 of 12 in San Diego: past the worst of the year but short of May, which is the month to book if the dates are open.

Rain falls on only 5 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 March day reached 32.5 °C and the coldest night fell to 6.9 °C.

March is moderately variable: 4 mm in the driest year against 102 mm in the wettest, around an average of 29 mm. Roughly two Marchs in three land near that average, and the third does something else entirely.

Wind is light at 8.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 68%.

How March sits in the year

Temperatures hold steady either side: 20.4 °C in February, 22.1 here, 23.3 in April. Nothing about the timing within the month matters much.

Daylight in March

11.9 hours of daylight, gaining 1 hours across the month. That is between San Diego's extremes of 14.3 and 10 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 15.5 °C in March — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 20.3 °C in September and bottoms out at 15.3 °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

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.

March in San Diego versus nearby

If San Diego is one option among several, the nearby comparison is worth making. Irvine is the weaker option in March — 4.7 °C cooler, the same number of rain days. Riverside is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: March works, with May the better month by 7 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in San Diego

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