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
With the arrival of September, DeKalb experiences a modest decline in average high-temperatures, transitioning from a moderately hot 78.4°F (25.8°C) in August to an agreeable 73°F (22.8°C). DeKalb, during September, witnesses an average low-temperature of 54.5°F (12.5°C).Humidity
In September, the average relative humidity is 80%.Rainfall
In September, the rain falls for 12.2 days. Throughout September, 2.24" (57mm) of precipitation is accumulated. In DeKalb, during the entire year, the rain falls for 152.6 days and collects up to 32.09" (815mm) of precipitation.Snowfall
In DeKalb, snow does not fall in June through September.Daylight
In DeKalb, the average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:21 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:37 pm CDT.
Sunshine
The average sunshine in September is 8.5h.UV index
In DeKalb, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for average individuals.Note: The maximum daily UV index of 4 in September converts into the following recommendations:
Take measures. Individuals with light skin might experience burns in under 30 minutes. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for DeKalb in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When 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
DeKalb, IL
- Average high temperature in September: 73°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in September: 54.5°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in September
DeKalb, 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
DeKalb, IL
- Average wind speed in September: 7.2mph
The windiest month (with the highest average wind speed) is April (10mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in September
DeKalb, IL
- Average humidity in September: 80%
The months with the highest relative humidity are January and July (85%).
The months with the lowest relative humidity are April and October (75%).
Average rainfall in September
DeKalb, IL
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.65").
Average rainfall days in September
DeKalb, IL
- Average rainfall days in September: 12.2 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (4.7 days).
Average snowfall in September
DeKalb, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.55").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
DeKalb, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
DeKalb, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 8h and 3min
The month with the most sunshine is July (Average sunshine: 9h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
DeKalb, IL
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is November (17.2 days).
The months with the least sunshine days are June and July (10.3 days).
Average UV index in September
DeKalb, IL
- Average UV index in September: 4
The months with the highest UV index are June and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
DeKalb, IL
- Average cloud cover in September: 35
The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are August and September (Cloud cover 35).
Average visibility in September
DeKalb, IL
- Average visibility in September: 5mi
The months with the highest visibility are March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, February, July, August and September (5mi).
DeKalb, Illinois, USA
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