The highest day temperature in September 2025 was 84°F. The lowest night temperature was 48°F. The average values for day and night temperatures during September were 75.3°F и 61.1°F respectivly.

The average sea surface temperature in September 2025 for New London was 70.9°F. The maximum and minimum values were 69.8°F and 73.4°F respectively.

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

Precipitation total in September for New London is 1.1 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 7.6 mph. It makes September one of the most windless months of the year for New London.

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 New London in September is 7.5 hours.