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
Charleston's weather subtly changes with the onset of September, barely falling from a moderately hot 75.9°F (24.4°C) in August to a pleasant 68°F (20°C). During the month of September, the temperature in Charleston generally drops to a low average of 48.6°F (9.2°C).Humidity
In Charleston, the average relative humidity in September is 79%.Rainfall
In September, the rain falls for 12.2 days. Throughout September, 2.44" (62mm) of precipitation is accumulated. Throughout the year, there are 154.3 rainfall days, and 32.68" (830mm) of precipitation is accumulated.Snowfall
In Charleston, snow does not fall in June through September.Daylight
In Charleston, the average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 5:58 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:33 am and sunset at 6:17 pm EDT.
Sunshine
In Charleston, the average sunshine in September is 8.1h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: An average maximum UV index of 4 in September leads to these recommendations:
Preventative actions are necessary - Recommendations to ward off sunburn are given. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Charleston 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?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Charleston have in September?
How high is the UV index in September?
Average temperature in September
Charleston, ME
- Average high temperature in September: 68°F
The warmest month (with the highest average high temperature) is July (77.2°F).
The month with the lowest average high temperature is January (23.9°F).
- Average low temperature in September: 48.6°F
The month with the highest average low temperature is July (55.9°F).
The coldest month (with the lowest average low temperature) is January (10.8°F).
Average pressure in September
Charleston, 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 (29.9"Hg).
Average wind speed in September
Charleston, ME
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (7.5mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Charleston, ME
- Average humidity in September: 79%
The month with the highest relative humidity is February (88%).
The month with the lowest relative humidity is May (76%).
Average rainfall in September
Charleston, ME
- Average rainfall in September: 2.44"
The wettest month (with the highest rainfall) is April (3.54").
The driest month (with the least rainfall) is July (1.89").
Average rainfall days in September
Charleston, ME
- Average rainfall days in September: 12.2 days
The months with the highest number of rainy days are May and July (16.7 days).
The month with the least rainy days is February (6.8 days).
Average snowfall in September
Charleston, ME
- Average snowfall in September: 0"
The month with the highest snowfall is February (11.26").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Charleston, ME
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (15.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Charleston, ME
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 1min
The month with the most sunshine is August (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 48min).
Average sunshine days in September
Charleston, ME
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is September (16.4 days).
The month with the least sunshine days is April (10.7 days).
Average UV index in September
Charleston, 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, October, November and December (UV index 2).
Average cloud cover in September
Charleston, ME
- Average cloud cover in September: 40
The month with the most cloud cover is February (Cloud cover 59).
The months with the least cloud cover are August and September (Cloud cover 40).
Average visibility in September
Charleston, ME
- Average visibility in September: 5mi
The months with the highest visibility are April, May, June, July, August, September, October, November and December (5mi).
The months with the lowest visibility are January, February and March (4mi).
Charleston, Maine, USA
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