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 weather during September records an average high-temperature of a still warm 79°F (26.1°C), closely mirroring the preceding month. September generally records an average low-temperature of 59.9°F (15.5°C).Humidity
In Caseyville, the average relative humidity in September is 75%.Rainfall
In Caseyville, in September, during 12.3 rainfall days, 2.13" (54mm) of precipitation is typically accumulated. Throughout the year, in Caseyville, there are 149.9 rainfall days, and 33.94" (862mm) of precipitation is accumulated.Snowfall
Months with snowfall in Caseyville are January through March, September, November and December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. In Caseyville, during the entire year, snow falls for 20.7 days and aggregates up to 7.13" (181mm) of snow.Daylight
The average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:29 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:43 pm CDT.
Sunshine
In Caseyville, the average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the average person.Note: In September, the maximum UV index of 5 suggests this advice:
Adopt protective measures - Suggestions to resist sunburn are offered. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September in Caseyville?
How many days does it rain in September?
When does it start to snow in Caseyville?
How many hours of daylight does Caseyville have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Caseyville have in September?
How high is the UV index in September?
Average temperature in September
Caseyville, IL
- Average high temperature in September: 79°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
Caseyville, 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
Caseyville, IL
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).
Average humidity in September
Caseyville, IL
- Average humidity in September: 75%
The months with the highest relative humidity are May, July and August (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Caseyville, IL
- Average rainfall in September: 2.13"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is February (1.77").
Average rainfall days in September
Caseyville, IL
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in September
Caseyville, IL
- Average snowfall in September: 0.04"
The month with the highest snowfall is January (2.13").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Caseyville, IL
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (7 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Caseyville, IL
- Average daylight in September: 12h and 2min
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 2min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in September
Caseyville, IL
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is December (18.6 days).
The month with the least sunshine days is May (11.6 days).
Average UV index in September
Caseyville, 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, November and December (UV index 2).
Average cloud cover in September
Caseyville, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are June and August (Cloud cover 28).
Average visibility in September
Caseyville, 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).
Caseyville, Illinois, USA
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