The highest day temperature in September 2025 was 78°F. The lowest night temperature was 52°F. The average values for day and night temperatures during September were 71.1°F и 63.9°F respectivly.

The average sea surface temperature in September 2025 for Chatham was 67.2°F. The maximum and minimum values were 65.4°F and 70.6°F respectively.

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

Precipitation total in September for Chatham is 1.1 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 11.5 mph. It makes September one of the most windless months of the year for Chatham.

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 Chatham in September is 7.4 hours.