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
As September begins, there is a minor decrease in the average high-temperature, softly falling from a moderately hot 78.4°F (25.8°C) in August to a pleasant 73°F (22.8°C). In DeKalb, the average nighttime temperature during September is a fresh 54.5°F (12.5°C).Humidity
The average relative humidity in September is 80%.Rainfall
In DeKalb, during September, the rain falls for 12.2 days and regularly aggregates up to 2.24" (57mm) of precipitation. Throughout the year, in DeKalb, there are 152.6 rainfall days, and 32.09" (815mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In DeKalb, the average length of the day in September is 12h and 28min.On the first day of September in DeKalb, 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
In September, the average sunshine in DeKalb, Illinois, is 8.5h.UV index
In September, the average daily maximum UV index in DeKalb, Illinois, is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: During September, 4 as the daily maximum UV index converts into the following advice:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Frequently asked questions
What is the usual temperature for DeKalb in September?
What is the average humidity in September in DeKalb?
How many days does it rain in September in DeKalb?
When it does not snow in DeKalb?
Does it snow in DeKalb in September?
How many hours of daylight does DeKalb have in September?
What time are sunrise and sunset in September in DeKalb?
How many hours of sunshine does DeKalb have in September?
What is the UV index intensity in September in DeKalb?
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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