Weather in San Diego in July

A good month. July works. It is not the peak, but nothing about it fights you. Highs average 31.9 °C, lows 19.3 °C, and rain falls on 1 days — nothing in the month is working against you.

July ranks 11 of 12 — near the bottom of San Diego's year. May is the month that works, and the swing between the two is 25 points, which is a different holiday rather than a slightly better one. Worth keeping in perspective: July is the weakest month of San Diego's year and it is still a perfectly good one. The downside here is small.

Rain falls on only 1 days, so an itinerary with no wet-weather fallback is a reasonable risk. Pack for 31.9 °C days and 19.3 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 5 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest July day reached 43.4 °C and the coldest night fell to 13.6 °C.

July is dependably dry, and that reliability is the point: across the twenty years measured, the wettest July on record still only managed 15 mm, and the driest managed 0 mm. There is no meaningful variability to plan around, which makes this one of the few months anywhere that you can build a fixed outdoor itinerary against without a fallback. The wettest single day in twenty years of Julys brought 8 mm. Rain simply is not the variable that decides this trip — heat, crowds and cost are.

Wind is light at 7.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 58%.

How July sits in the year

Temperatures hold steady either side: 28.4 °C in June, 31.9 here, 32.7 in August. Nothing about the timing within the month matters much.

Daylight in July

July is at or near the longest days of San Diego's year: 14.1 hours of daylight, losing 0.5 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

Sea temperature

The sea sits at about 18.9 °C in July — swimmable, but it takes a moment to commit. 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

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.

July in San Diego versus nearby

If San Diego is one option among several, the nearby comparison is worth making. Irvine is a better bet in July — 9.5 °C cooler, 1 day less rain. Riverside is the weaker option in July — 4.7 °C warmer, the same number of rain days.

So: July is a compromise. May is 22 points better and is what San Diego 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 Diego

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