Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The arrival of September signals a subtle shift in temperature, down from an agreeable 72.3°F (22.4°C) in August to an enjoyable 63.5°F (17.5°C). Throughout September, Grand Isle records an average temperature of 45.1°F (7.3°C) at night.Humidity
The average relative humidity in September is 81%.Rainfall
In September, the rain falls for 13.1 days. Throughout September, 2.05" (52mm) of precipitation is accumulated. Throughout the year, there are 140.8 rainfall days, and 30.12" (765mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
The average length of the day in September is 12h and 33min.On the first day of September, sunrise is at 5:52 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:31 am and sunset at 6:13 pm EDT.
Sunshine
In September, the average sunshine is 7.3h.UV index
In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: A maximum high daily UV index of 3 during September translates into the following directions:
Undertake precautions - It is suggested to shield oneself from sunburn. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Grand Isle have in September?
When is the sunrise / sunset in September in Grand Isle?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Grand Isle, ME
- Average high temperature in September: 63.5°F
The warmest month (with the highest average high temperature) is July (74.3°F).
The month with the lowest average high temperature is January (18°F).
- Average low temperature in September: 45.1°F
The month with the highest average low temperature is July (53.6°F).
The coldest month (with the lowest average low temperature) is January (2.8°F).
Average pressure in September
Grand Isle, ME
- Average pressure in September: 30.01"Hg
The months with the highest atmospheric pressure are March, September and November (30.01"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Grand Isle, ME
- Average wind speed in September: 6.8mph
The windiest months (with the highest average wind speed) are January and February (8.2mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
Grand Isle, ME
- Average humidity in September: 81%
The month with the highest relative humidity is March (94%).
The month with the lowest relative humidity is May (76%).
Average rainfall in September
Grand Isle, ME
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is April (2.95").
The driest month (with the least rainfall) is February (1.97").
Average rainfall days in September
Grand Isle, ME
- Average rainfall days in September: 13.1 days
The month with the highest number of rainy days is July (17.1 days).
The months with the least rainy days are January and February (4.3 days).
Average snowfall in September
Grand Isle, ME
- Average snowfall in September: 0"
The month with the highest snowfall is January (14.92").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Grand Isle, ME
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (21.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grand Isle, ME
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 7h and 2min
The month with the most sunshine is August (Average sunshine: 9h and 30min).
The month with the least sunshine is February (Average sunshine: 2h and 6min).
Average sunshine days in September
Grand Isle, ME
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is September (14.5 days).
The month with the least sunshine days is April (7.9 days).
Average UV index in September
Grand Isle, ME
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).
Average cloud cover in September
Grand Isle, ME
- Average cloud cover in September: 44
The month with the most cloud cover is February (Cloud cover 75).
The month with the least cloud cover is July (Cloud cover 42).
Average visibility in September
Grand Isle, ME
- Average visibility in September: 5mi
The months with the highest visibility are May, June, July, August, September, October and November (5mi).
The months with the lowest visibility are January, February, March, April and December (4mi).
Grand Isle, Maine, USA
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