Ocean temperatureIn Bar Harbor, in September, the average water temperature is 55.9☏. SnowfallIn Bar Harbor, Maine, snow does not fall in June through September. In Bar Harbor, during the entire year, the rain falls for 142.1 days and collects up to 32.28' of precipitation. Throughout September, 1.81' of precipitation is accumulated. Rainfall In September, the rain falls for 10.5 days. HumidityThe average relative humidity in September in Bar Harbor is 79%. Bar Harbor records an average low of 52.7☏ throughout the nights in September. TemperatureThe arrival of September suggests a slight decrease in the average high-temperature, moving from a moderately hot 73.4☏ in August to a refreshing 67.1☏. As daylight hours begin to shorten, the city gears up for the arrival of cooler temperatures. Harvest festivals and hiking are popular, providing visitors with a beautiful backdrop.

Trees start to change their colors, providing an impressive palette of fall hues.

There is no snowfall during this month, indicating the lasting warmth of summer. September marks a noticeable shift in Bar Harbor's weather as it makes its transition from summer to fall.