September weather forecastCharleston, IL
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Charleston, Illinois, with temperature in the range of an average low of 58.5°F (14.7°C) and an average high of 77.2°F (25.1°C).Temperature
The onset of September brings with it an average high-temperature of a still moderately hot 77.2°F (25.1°C), showing a negligible variation from the month before. Throughout September, the temperature falls to an average low of 58.5°F (14.7°C).Humidity
In Charleston, the average relative humidity in September is 76%.Rainfall
In Charleston, in September, during 12.1 rainfall days, 1.38" (35mm) of precipitation is typically accumulated. In Charleston, during the entire year, the rain falls for 148 days and collects up to 25.63" (651mm) of precipitation.Snowfall
May through September are months without snowfall in Charleston.Daylight
The average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:36 pm CDT.
Sunshine
The average sunshine in September is 8.9h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: An average maximum UV index of 5 in September leads to these recommendations:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. To protect against the Sun's most potent rays, avoid direct exposure 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
Charleston, IL
- Average high temperature in September: 77.2°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).
- Average low temperature in September: 58.5°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).
Average pressure in September
Charleston, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Charleston, IL
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).
Average humidity in September
Charleston, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Charleston, IL
- Average rainfall in September: 1.38"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in September
Charleston, IL
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in September
Charleston, IL
- Average snowfall in September: 0"
The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Charleston, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Charleston, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Charleston, IL
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in September
Charleston, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Charleston, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 31).
Average visibility in September
Charleston, IL
- 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).
