September weather forecastSullivan, ME
September
Weather in September
September, the first month of the autumn in Sullivan, is also an enjoyable month, with temperature in the range of an average low of 52.7°F (11.5°C) and an average high of 67.1°F (19.5°C).Temperature
In Sullivan, entering September brings a subtle temperature decrement, reducing from August's warm 73.4°F (23°C) to a comfortable 67.1°F (19.5°C). Sullivan records a consistent low-temperature of 52.7°F (11.5°C) during September nights.Humidity
The average relative humidity in September is 79%.Rainfall
In Sullivan, during September, the rain falls for 10.5 days and regularly aggregates up to 1.81" (46mm) of precipitation. Throughout the year, there are 142.1 rainfall days, and 32.28" (820mm) of precipitation is accumulated.Snowfall
In Sullivan, snow does not fall in June through September.Ocean temperature
In Sullivan, in September, the average water temperature is 55.8°F (13.2°C).Note: To swim in 55.8°F (13.2°C) at less than 50°F (10°C), ensure you're well-protected. Without it, be prepared for a sudden jolt of cold and breathing issues. Remember, even 55.4°F (13°C) is not welcoming.
Daylight
The average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 5:56 am and sunset at 7:08 pm. On the last day of the month, sunrise is at 6:30 am and sunset at 6:14 pm EDT.
Sunshine
The average sunshine in September is 8.2h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Undertake precautions - It is suggested to shield oneself from sunburn. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sullivan, ME
- Average high temperature in September: 67.1°F
The warmest month (with the highest average high temperature) is August (73.4°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in September: 52.7°F
The month with the highest average low temperature is July (58.1°F).
The coldest month (with the lowest average low temperature) is January (18.5°F).
Average pressure in September
Sullivan, ME
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is September (30.04"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Sullivan, ME
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in September
Sullivan, ME
- Average humidity in September: 79%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is November (76%).
Average rainfall in September
Sullivan, ME
- Average rainfall in September: 1.81"
The wettest month (with the highest rainfall) is December (3.94").
The driest month (with the least rainfall) is July (1.57").
Average rainfall days in September
Sullivan, ME
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is April (15.5 days).
The month with the least rainy days is February (7.5 days).
Average snowfall in September
Sullivan, ME
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.75").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Sullivan, ME
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Sullivan, ME
- Average sea temperature in September: 55.6°F
The best month for swimming (with the highest average sea temperature) is August (56.8°F).
The coldest month (with the lowest average sea temperature) is March (38°F).
Average daylight in September /
Average sunshine in September
Sullivan, ME
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 8h and 12min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 6min).
Average sunshine days in September
Sullivan, ME
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is August (18.7 days).
The month with the least sunshine days is April (11.2 days).
Average UV index in September
Sullivan, ME
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Sullivan, ME
- Average cloud cover in September: 35
The month with the most cloud cover is February (Cloud cover 56).
The months with the least cloud cover are August and September (Cloud cover 35).
Average visibility in September
Sullivan, ME
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).





