The highest day temperature in September 2025 was 98°F. The lowest night temperature was 76°F. The average values for day and night temperatures during September were 91.2°F и 79.4°F respectivly.

The average sea surface temperature in September 2025 for St. Petersburg was 87.9°F. The maximum and minimum values were 85.4°F and 90.4°F respectively.

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

Precipitation total in September for St. Petersburg is 1.8 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 9.6 mph. It makes September one of the most windless months of the year for St. Petersburg.

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 St. Petersburg in September is 6.6 hours.