September weather forecastUnion, IL
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Union, Illinois, with an average temperature fluctuating between 72.1°F (22.3°C) and 54.1°F (12.3°C).Temperature
The onset of September brings a small shift in high-temperatures, falling from a moderately hot 78.1°F (25.6°C) in August to a pleasant 72.1°F (22.3°C). In Union, September nights cool down to an average of 54.1°F (12.3°C).Humidity
The average relative humidity in September is 81%.Rainfall
In Union, in September, during 12.8 rainfall days, 2.09" (53mm) of precipitation is typically accumulated. In Union, during the entire year, the rain falls for 154.6 days and collects up to 30.31" (770mm) of precipitation.Snowfall
In Union, snow does not fall in May through September.Daylight
In Union, Illinois, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:20 am and sunset at 7:27 pm. On the last day of September, sunrise is at 6:50 am and sunset at 6:36 pm CDT.
Sunshine
In Union, Illinois, the average sunshine in September is 8.5h.UV index
The average daily maximum UV index in September in Union is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: The UV index of 4 in September translates into these instructions:
Take precautions - Protection against sunburn is recommended. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Union, IL
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (26.1°F).
- Average low temperature in September: 54.1°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).
Average pressure in September
Union, 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
Union, IL
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is April (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in September
Union, IL
- Average humidity in September: 81%
The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is October (76%).
Average rainfall in September
Union, IL
- Average rainfall in September: 2.09"
The wettest month (with the highest rainfall) is June (4.21").
The driest months (with the least rainfall) are February and November (1.5").
Average rainfall days in September
Union, IL
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is July (19.3 days).
The month with the least rainy days is February (4.8 days).
Average snowfall in September
Union, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Union, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.3 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
Union, IL
- Average daylight in September: 12h and 30min
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 30min
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
Union, IL
- Average sunshine days in September: 14.8 days
The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is June (9.5 days).
Average UV index in September
Union, IL
- Average UV index in September: 4
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Union, 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
Union, 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).
