September weather forecastDe Witt, IL
September
Weather in September
September, the first month of the autumn in De Witt, is still a warm month, with an average temperature fluctuating between 58.1°F (14.5°C) and 75.9°F (24.4°C).Temperature
The transition into September marks the average high-temperature at a still warm 75.9°F (24.4°C), differing minimally from August's 80.2°F (26.8°C). De Witt reports a consistent average low-temperature of 58.1°F (14.5°C) throughout September nights.Humidity
In September, the average relative humidity in De Witt is 76%.Rainfall
In September, in De Witt, the rain falls for 10.7 days. Throughout September, 1.34" (34mm) of precipitation is accumulated. In De Witt, Illinois, during the entire year, the rain falls for 138.7 days and collects up to 20.91" (531mm) of precipitation.Snowfall
In De Witt, snow does not fall in May through October.Daylight
The average length of the day in September in De Witt is 12h and 26min.On the first day of September, sunrise is at 6:23 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:38 pm CDT.
Sunshine
In September, the average sunshine is 9.1h.UV index
The average daily maximum UV index in September in De Witt is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the average person.Note: The average daily UV index of 5 in September transforms into the following instructions:
Undertake precautions - It is suggested to shield oneself from sunburn. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
De Witt, IL
- Average high temperature in September: 75.9°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (31.5°F).
- Average low temperature in September: 58.1°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 (19.9°F).
Average pressure in September
De Witt, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
De Witt, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is January (10.9mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
De Witt, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
De Witt, IL
- Average rainfall in September: 1.34"
The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is December (1.1").
Average rainfall days in September
De Witt, IL
- Average rainfall days in September: 10.7 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in September
De Witt, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.76").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
De Witt, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.6 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
De Witt, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 9h and 6min
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
De Witt, IL
- Average sunshine days in September: 16.6 days
The month with the most sunshine days is November (19.2 days).
The month with the least sunshine days is May (10.4 days).
Average UV index in September
De Witt, IL
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
De Witt, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in September
De Witt, 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).
