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 average high-temperature in September, at a still moderately hot 77.9°F (25.5°C), reveals a modest deviation from August's 82.6°F (28.1°C). During the nights in September, the temperature in Chesterfield, Illinois, averages to a moderate 59.4°F (15.2°C).Humidity
In September, the average relative humidity in Chesterfield is 75%.Rainfall
In Chesterfield, during September, the rain falls for 11.5 days and regularly aggregates up to 1.73" (44mm) of precipitation. Throughout the year, in Chesterfield, Illinois, there are 138.2 rainfall days, and 23.31" (592mm) of precipitation is accumulated.Snowfall
In Chesterfield, Illinois, snow does not fall in April through October.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:30 pm. On the last day of September, in Chesterfield, sunrise is at 6:56 am and sunset at 6:43 pm CDT.
Sunshine
In Chesterfield, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September in Chesterfield is 5. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: A daily maximum UV index of 5 in September translates into the following instructions:
Guard yourself - Precautionary measures against sun damage are advocated. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Frequently asked questions
What is the average September temperature in Chesterfield?
What is the average humidity in September in Chesterfield?
How much does it rain in Chesterfield in September?
When it does not snow in Chesterfield?
How many hours of daylight does Chesterfield have in September?
What time are sunrise and sunset in September in Chesterfield?
How many hours of sunshine does Chesterfield have in September?
How high is the UV index in September in Chesterfield?
Average temperature in September
Chesterfield, IL
- Average high temperature in September: 77.9°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (34.9°F).
- Average low temperature in September: 59.4°F
The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Chesterfield, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Chesterfield, IL
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).
Average humidity in September
Chesterfield, IL
- Average humidity in September: 75%
The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Chesterfield, IL
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is June (3.07").
The driest months (with the least rainfall) are January and February (1.22").
Average rainfall days in September
Chesterfield, IL
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Chesterfield, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Chesterfield, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (6.3 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
Chesterfield, IL
- Average daylight in September: 12h and 2min
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 30min).
- Average sunshine in September: 9h and 2min
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 24min).
Average sunshine days in September
Chesterfield, IL
- Average sunshine days in September: 16 days
The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.1 days).
Average UV index in September
Chesterfield, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Chesterfield, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are August and September (Cloud cover 29).
Average visibility in September
Chesterfield, IL
- 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).
Chesterfield, Illinois, USA
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