The highest day temperature in September 2025 was 93°F. The lowest night temperature was 65°F. The average values for day and night temperatures during September were 82.8°F и 69.2°F respectivly.

The average sea surface temperature in September 2025 for Irvine was 71.5°F. The maximum and minimum values were 68.2°F and 74.4°F respectively.

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

Precipitation total in September for Irvine is 0.0 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 5.2 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 Irvine in September is 10.5 hours.