The highest day temperature in September 2026 was 91°F. The lowest night temperature was 56°F. The average values for day and night temperatures during September were 76.0°F и 65.4°F respectivly.

The average sea surface temperature in September 2026 for Fire Island was 73.0°F. The maximum and minimum values were 62.2°F and 78.4°F respectively.

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

Precipitation total in September for Fire Island is 1.4 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 9.4 mph. It makes September one of the most windless months of the year for Fire Island.

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 Fire Island in September is 7.3 hours.