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
In September, the average high-temperature marginally decreases from 80.1°F (26.7°C) in August to a still moderately hot 73.9°F (23.3°C). Thornton throughout September, records an average low-temperature of 58.3°F (14.6°C).Humidity
In September, the average relative humidity is 76%.Rainfall
In September, the rain falls for 13.4 days. Throughout September, 2.48" (63mm) of precipitation is accumulated. Throughout the year, there are 155.6 rainfall days, and 31.3" (795mm) of precipitation is accumulated.Snowfall
In Thornton, Illinois, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:33 pm CDT.
Sunshine
In Thornton, the average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the average person.Note: During September, 4 as the daily maximum UV index converts into the following advice:
Exercise prevention - Warding off sunburn is urged. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Enhance your sun protection with tightly woven, yet airy clothing.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How much does it rain in Thornton in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Thornton have in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Thornton, IL
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in September: 58.3°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 (18.9°F).
Average pressure in September
Thornton, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Thornton, IL
- Average wind speed in September: 7.3mph
The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in September
Thornton, IL
- Average humidity in September: 76%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Thornton, IL
- Average rainfall in September: 2.48"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").
Average rainfall days in September
Thornton, IL
- Average rainfall days in September: 13.4 days
The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in September
Thornton, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Thornton, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Thornton, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Thornton, IL
- Average sunshine days in September: 14 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).
Average UV index in September
Thornton, IL
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Thornton, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Thornton, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Thornton, Illinois, USA
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