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
Knoxville's shift into September sets the average high-temperature at a still moderately hot 75.6°F (24.2°C), a figure that deviates only slightly from August's 80.6°F (27°C). Throughout September, the nighttime temperature averages to a mild 56.3°F (13.5°C).Humidity
The average relative humidity in September is 76%.Rainfall
In Knoxville, during September, the rain falls for 8.7 days and regularly aggregates up to 1.02" (26mm) of precipitation. Throughout the year, there are 109.9 rainfall days, and 11.14" (283mm) of precipitation is accumulated.Snowfall
In Knoxville, snow does not fall in May through September.Daylight
In Knoxville, the average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:44 pm CDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
In Knoxville, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.Note: The maximum daily UV index of 4 during September translates into the following directions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. Minimize direct exposure to the Sun during midday when its radiation is at its peak. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Knoxville in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow in Knoxville?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Knoxville have in September?
What is the UV index reading in September?
Average temperature in September
Knoxville, IL
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in September
Knoxville, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Knoxville, IL
- Average wind speed in September: 7.9mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in September
Knoxville, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Knoxville, IL
- Average rainfall in September: 1.02"
The wettest month (with the highest rainfall) is May (1.65").
The driest months (with the least rainfall) are January and December (0.47").
Average rainfall days in September
Knoxville, IL
- Average rainfall days in September: 8.7 days
The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is February (3.9 days).
Average snowfall in September
Knoxville, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.38").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Knoxville, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.8 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
Knoxville, 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 18min).
- Average sunshine in September: 9h and 1min
The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Knoxville, IL
- Average sunshine days in September: 18.4 days
The month with the most sunshine days is December (21.6 days).
The month with the least sunshine days is June (12.4 days).
Average UV index in September
Knoxville, 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
Knoxville, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in September
Knoxville, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Knoxville, Illinois, USA
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