The highest day temperature in August 2025 was 91°F. The lowest night temperature was 57°F. The average values for day and night temperatures during August were 80.2°F и 65.0°F respectivly.

The average sea surface temperature in August 2025 for Groton was 72.6°F. The maximum and minimum values were 70.8°F and 76.8°F respectively.

You can expect various weather conditions during August. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in August for Groton is 1.1 in. This value is relatively stable throughout the year.

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

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 Groton in August is 7.8 hours.