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 commencement of September introduces an average high-temperature of a still warm 77.5°F (25.3°C), closely mirroring the preceding month. An average low-temperature of 58.8°F (14.9°C) is recorded in the month of September in Chatham.Humidity
In September, the average relative humidity is 75%.Rainfall
In Chatham, in September, during 9.1 rainfall days, 0.63" (16mm) of precipitation is typically accumulated. In Chatham, Illinois, during the entire year, the rain falls for 104.2 days and collects up to 9.29" (236mm) of precipitation.Snowfall
In Chatham, snow does not fall in May through October.Daylight
In Chatham, Illinois, the average length of the day in September is 12h and 26min.On the first day of September in Chatham, sunrise is at 6:27 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:42 pm CDT.
Sunshine
The average sunshine in September in Chatham is 9.3h.UV index
In Chatham, Illinois, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for average individuals.Note: The maximum daily UV index, 5 in September, converts into the following recommendations:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Chatham?
What is the average humidity in September in Chatham?
How many days does it rain in September in Chatham?
When it does not snow in Chatham?
How many hours of daylight does Chatham have in September?
When is the sunrise / sunset in September in Chatham?
How long on average sun shines in September in Chatham?
How high is the UV index in September in Chatham?
Average temperature in September
Chatham, IL
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.6°F).
- Average low temperature in September: 58.8°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (21.4°F).
Average pressure in September
Chatham, 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 (29.91"Hg).
Average wind speed in September
Chatham, IL
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is July (6.1mph).
Average humidity in September
Chatham, IL
- Average humidity in September: 75%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Chatham, IL
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is June (1.22").
The driest month (with the least rainfall) is December (0.43").
Average rainfall days in September
Chatham, IL
- Average rainfall days in September: 9.1 days
The month with the highest number of rainy days is May (12.5 days).
The month with the least rainy days is January (4.4 days).
Average snowfall in September
Chatham, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.91").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Chatham, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.7 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
Chatham, 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 24min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Chatham, IL
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is December (22.6 days).
The month with the least sunshine days is June (14 days).
Average UV index in September
Chatham, 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
Chatham, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are June and September (Cloud cover 29).
Average visibility in September
Chatham, 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).
Chatham, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location