September and October are San Diego's best months

If you can choose when to spend a month in San Diego, choose September or October. The ocean is at its warmest, the June-gloom marine layer is gone, and the beaches empty out after Labor Day.

What the weather actually does

Days sit in the high 70s to low 80s inland and low-to-mid 70s at the coast, with clear mornings instead of overcast ones. Occasional Santa Ana conditions push inland temperatures higher for a few days at a time.

What is on

• Warmest ocean swimming of the year, roughly 68-72°F.
• Fall hiking in Cuyamaca and the Lagunas without summer heat.
• Julian apple season, an hour from El Cajon.
• Quieter Balboa Park museums and zoo mornings.

Booking implications

Demand for mid-term stays softens between the summer peak and the winter snowbird season, so early-fall arrivals often get the most flexibility on dates.