The highest day temperature in September 2026 was 104°F. The lowest night temperature was 63°F. The average values for day and night temperatures during September were 81.7°F и 72.0°F respectivly.

The average sea surface temperature in September 2026 for San Diego was 76.3°F. The maximum and minimum values were 74.4°F and 77.8°F respectively.

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation total in September for San Diego is 0.1 in. It makes september the least rainy month of the year.

The average wind speed in September is 6.7 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for San Diego in September is 9.2 hours.