The highest day temperature in September 2026 was 82°F. The lowest night temperature was 43°F. The average values for day and night temperatures during September were 66.9°F и 53.2°F respectivly.

The average sea surface temperature in September 2026 for Bar Harbor was 58.0°F. The maximum and minimum values were 55.0°F and 61.6°F respectively.

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

Precipitation total in September for Bar Harbor is 1.4 in. It makes september one of the most rainy months 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 Bar Harbor.

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 Bar Harbor in September is 6.9 hours.