San Diego
California, USA
Long term weather forecast
Long term weather forecast

September weather forecast and Climate
San Diego, CA

  • Average high temperature in September: 75.9°F

Warmest month (with highest average high temperature) is August (76.4°F).
Month with lowest average high temperature is December (64.7°F).

  • Average low temperature in September: 65.2°F

Month with highest average low temperature is August (66.7°F).
Coldest month (with lowest average low temperature) is December (48.4°F).

  • Average humidity in September: 72.7%

Month with highest relative humidity is July (74.6%).
Month with lowest relative humidity is January (63.1%).

  • Average rainfall in September: 0.2"

Wettest month (with highest rainfall) is January (2.1").
Driest month (with lowest rainfall) is July (0").

  • Average rainfall days in September: 1.2 days

Month with highest number of rainy days is February (7.1 days).
Month with lowest number of rainy days is August (0.4 days).

  • Average sea temperature in September: 68°F

Best months for swimming (with highest average sea temperature) are August and September (68°F).
Coldest months (with lowest average sea temperature) are January, February, March and April (59°F).

  • Average daylight in September: 12h

Months with longest days are May, June and July (Average daylight: 14h).
Months with shortest days are January, November and December (Average daylight: 10h).

  • Average sunshine in September: 8.4h

Month with most sunshine is July (Average sunshine: 9.8h).
Month with least sunshine is December (Average sunshine: 7.5h).

  • Average UV index in September: 8

Months with highest UV index are June, July and August (UV index 10).
Months with lowest UV index are January and December (UV index 3).