San Diego County in April

September through November gives you the best weather with the fewest crowds. Ocean temperatures peak in September at 72°F, and hotel rates drop after Labor Day. October brings perfect hiking weather to the inland areas. March through May offers wildflower blooms in Anza-Borrego Desert and comfortable temperatures countywide. But spring break crowds pack the beaches, and hotel prices spike. Summer means marine layer - that gray marine fog that rolls in most mornings and burns off by afternoon. Coastal areas stay cool (65-75°F), while inland valleys hit 85-95°F. Beach parking becomes a blood sport on weekends. Winter rarely dips below 60°F, making it perfect for outdoor activities. You might catch some rain December through February, but it usually clears quickly. This is when locals have the beaches mostly to themselves.