September weather forecastDeer Isle, ME
September
Weather in September
Weather patterns in Deer Isle, Maine begin to change in September. A drop in temperature to an average of 63.9°F (17.7°C), signals the onset of the fall season. Even though temperatures begin to decrease, the weather remains comfortably warm for the better part of the month. It's the perfect time to experience the beautiful fall foliage as leaves change color. The decline in humidity levels also makes outdoor activities more comfortable.Temperature
With the onset of September, a modest change to a refreshing 63.9°F (17.7°C) from August's 68.9°F (20.5°C) is noted in high-temperature. Throughout September, the average low-temperature in Deer Isle dips to a fresh 54.7°F (12.6°C).Humidity
In September, the average relative humidity is 82%.Rainfall
September is the month with the least rainfall. Rain falls for 8.7 days and accumulates 0.91" (23mm) of precipitation.Snowfall
In Deer Isle, snow does not fall in May through September.Ocean temperature
In September, the average ocean temperature is 56.8°F (13.8°C).Note: Beware of 56.8°F (13.8°C) waters at 55.4°F (13°C), they're uninviting, and a dip below 50°F (10°C) has risks of breath loss and cold shock, contingent on health.
Daylight
In September, the average length of the day is 12h and 30min.On the first day of September, sunrise is at 5:58 am and sunset at 7:10 pm. On the last day of the month, sunrise is at 6:32 am and sunset at 6:16 pm EDT.
Sunshine
The average sunshine in September is 8.5h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: During September, 4 as the daily maximum UV index converts into the following advice:
Heed the precautions - It is counselled to guard against solar damage. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Deer Isle, ME
- Average high temperature in September: 63.9°F
The warmest month (with the highest average high temperature) is August (68.9°F).
The month with the lowest average high temperature is January (31.5°F).
- Average low temperature in September: 54.7°F
The month with the highest average low temperature is August (59.9°F).
The coldest month (with the lowest average low temperature) is January (21°F).
Average pressure in September
Deer Isle, 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
Deer Isle, ME
- Average wind speed in September: 9.2mph
The windiest month (with the highest average wind speed) is January (14.4mph).
The calmest months (with the lowest average wind speed) are July and August (7.8mph).
Average humidity in September
Deer Isle, ME
- Average humidity in September: 82%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is November (76%).
Average rainfall in September
Deer Isle, ME
- Average rainfall in September: 0.91"
The wettest month (with the highest rainfall) is October (2.09").
The driest month (with the least rainfall) is September (0.91").
Average rainfall days in September
Deer Isle, ME
- Average rainfall days in September: 8.7 days
The month with the highest number of rainy days is July (12.8 days).
The month with the least rainy days is February (5.3 days).
Average snowfall in September
Deer Isle, ME
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.32").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Deer Isle, ME
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.7 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in September
Deer Isle, ME
- Average sea temperature in September: 56.8°F
The best month for swimming (with the highest average sea temperature) is August (58.6°F).
The coldest month (with the lowest average sea temperature) is March (38.2°F).
Average daylight in September /
Average sunshine in September
Deer Isle, 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 30min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is December (Average sunshine: 4h and 30min).
Average sunshine days in September
Deer Isle, ME
- Average sunshine days in September: 19.9 days
The month with the most sunshine days is September (19.9 days).
The month with the least sunshine days is July (15.4 days).
Average UV index in September
Deer Isle, 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
Deer Isle, ME
- Average cloud cover in September: 32
The months with the most cloud cover are February and March (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Deer Isle, ME
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
