The highest day temperature in September 2024 was 86°F. The lowest night temperature was 49°F. The average values for day and night temperatures during September were 72.4°F и 56.6°F respectivly.

The average sea surface temperature in September 2024 for Portsmouth was 62.4°F. The maximum and minimum values were 59.6°F and 66.6°F respectively.

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

Precipitation total in September for Portsmouth is 0.9 in. It makes september the least rainy month of the year.

The average wind speed in September is 7.2 mph. It makes September one of the most windless months of the year for Portsmouth.

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 Portsmouth in September is 7.5 hours.