September weather forecastCahokia, IL
September
Weather in September
September, the first month of the autumn in Cahokia, is also a moderately hot month, with an average temperature ranging between max 79.3°F (26.3°C) and min 59.9°F (15.5°C).Temperature
The transition into September involves a small decrease in the average high-temperature, dipping slightly from a moderately hot 84.9°F (29.4°C) in August to a still warm 79.3°F (26.3°C). Cahokia anticipates an average minimum temperature of 59.9°F (15.5°C) in the month of September.Humidity
In September, the average relative humidity is 74%.Rainfall
In Cahokia, during September, the rain falls for 12.6 days and regularly aggregates up to 2.28" (58mm) of precipitation. Throughout the year, there are 152.2 rainfall days, and 36.46" (926mm) of precipitation is accumulated.Snowfall
In Cahokia, snow does not fall in April through October.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of September, in Cahokia, sunrise is at 6:56 am and sunset at 6:44 pm CDT.
Sunshine
In September, the average sunshine in Cahokia, Illinois, is 9.4h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Preventative actions are necessary - Recommendations to ward off sunburn are given. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Cahokia, IL
- Average high temperature in September: 79.3°F
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).
Average pressure in September
Cahokia, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Cahokia, IL
- Average wind speed in September: 6mph
The windiest month (with the highest average wind speed) is January (9.3mph).
The calmest month (with the lowest average wind speed) is July (5.5mph).
Average humidity in September
Cahokia, IL
- Average humidity in September: 74%
The months with the highest relative humidity are May and July (78%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Cahokia, IL
- Average rainfall in September: 2.28"
The wettest month (with the highest rainfall) is May (4.53").
The driest month (with the least rainfall) is February (2.01").
Average rainfall days in September
Cahokia, IL
- Average rainfall days in September: 12.6 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (7.7 days).
Average snowfall in September
Cahokia, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.44").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Cahokia, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.4 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
Cahokia, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 24min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in September
Cahokia, IL
- Average sunshine days in September: 15.4 days
The month with the most sunshine days is October (18.7 days).
The month with the least sunshine days is May (10.7 days).
Average UV index in September
Cahokia, IL
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
Cahokia, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Cahokia, 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).
