September weather forecastBelfast, ME
September
Weather in September
In September, Belfast, Maine, transitions from the warm temperatures of late summer to the cool early onset of fall. The weather undergoes marked changes, rain being a constant pattern across this month. Equally notable is the drop in high temperatures, from 73.9°F (23.3°C) in August to a more relaxed 67.1°F (19.5°C). September brings the promise of the upcoming fall season's beauty, as trees start to change color, and the cool breeze becomes more prevalent. Evenings spent by the fire, apple picking, and foliage viewing all become more frequent activities during this time.Temperature
The shift from August to September coincides with a small decrease in the average high-temperature, down to a refreshing 67.1°F (19.5°C) from a warm 73.9°F (23.3°C). Belfast throughout September, experiences an average nighttime temperature of 51.1°F (10.6°C).Humidity
The average relative humidity in September is 80%.Rainfall
The months with the least rainfall are July and September Rain falls for 10.2 days and accumulates 1.46" (37mm) of rain.Snowfall
June through September are months without snowfall.Ocean temperature
In Belfast, Maine, in September, the average water temperature is 58.3°F (14.6°C).Note: Swimming in 58.3°F (14.6°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.
Daylight
The average length of the day in September is 12h and 30min.On the first day of September, sunrise is at 5:59 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:33 am and sunset at 6:18 pm EDT.
Sunshine
In Belfast, the average sunshine in September is 8.1h.UV index
In Belfast, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A daily high UV index of 4 in September leads to these guidelines:
Take precautions - Protection against skin and eye damage is obliged. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Belfast, ME
- Average high temperature in September: 67.1°F
The warmest months (with the highest average high temperature) are July and August (73.9°F).
The month with the lowest average high temperature is January (28.4°F).
- Average low temperature in September: 51.1°F
The month with the highest average low temperature is July (57.7°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).
Average pressure in September
Belfast, 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
Belfast, ME
- Average wind speed in September: 6.8mph
The windiest month (with the highest average wind speed) is March (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).
Average humidity in September
Belfast, ME
- Average humidity in September: 80%
The months with the highest relative humidity are February and July (83%).
The month with the lowest relative humidity is November (77%).
Average rainfall in September
Belfast, ME
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is December (2.72").
The driest months (with the least rainfall) are July and September (1.46").
Average rainfall days in September
Belfast, ME
- Average rainfall days in September: 10.2 days
The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (7.1 days).
Average snowfall in September
Belfast, ME
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.57").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Belfast, ME
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Belfast, ME
- Average sea temperature in September: 58.3°F
The best month for swimming (with the highest average sea temperature) is August (60.4°F).
The coldest month (with the lowest average sea temperature) is March (37.8°F).
Average daylight in September /
Average sunshine in September
Belfast, 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 6min
The month with the most sunshine is August (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 4h and 18min).
Average sunshine days in September
Belfast, ME
- Average sunshine days in September: 17.9 days
The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is April (11.7 days).
Average UV index in September
Belfast, 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
Belfast, ME
- Average cloud cover in September: 37
The month with the most cloud cover is March (Cloud cover 55).
The months with the least cloud cover are August and September (Cloud cover 37).
Average visibility in September
Belfast, ME
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, October, November and December (6mi).
The months with the lowest visibility are May, June, July, August and September (5mi).
