September weather forecastWilmette, IL
September
Weather in September
September, the first month of the autumn in Wilmette, is also an agreeable month, with an average temperature fluctuating between 70.7°F (21.5°C) and 61.7°F (16.5°C).Temperature
A modest decline in the average high-temperature is seen during September, decreasing from a moderately hot 77°F (25°C) in August to an agreeable 70.7°F (21.5°C). The month of September in Wilmette is marked by an average minimum temperature of 61.7°F (16.5°C), slightly cooler than its daytime counterpart.Humidity
In Wilmette, the average relative humidity in September is 75%.Rainfall
In Wilmette, Illinois, in September, it is raining for 14.9 days, with typically 3.11" (79mm) of accumulated precipitation. In Wilmette, during the entire year, the rain falls for 154.1 days and collects up to 33.31" (846mm) of precipitation.Snowfall
May through September are months without snowfall in Wilmette.Daylight
In September, the average length of the day in Wilmette is 12h and 28min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:33 pm CDT.
Sunshine
In September, the average sunshine is 9h.UV index
The average daily maximum UV index in September in Wilmette is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the average person.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Boost your sun resistance with garments that are densely woven yet spacious.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Wilmette, IL
- Average high temperature in September: 70.7°F
The warmest month (with the highest average high temperature) is August (77°F).
The month with the lowest average high temperature is January (29.1°F).
- Average low temperature in September: 61.7°F
The months with the highest average low temperature are July and August (68°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in September
Wilmette, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Wilmette, IL
- Average wind speed in September: 9.6mph
The windiest month (with the highest average wind speed) is January (12.7mph).
The calmest months (with the lowest average wind speed) are July and August (8mph).
Average humidity in September
Wilmette, IL
- Average humidity in September: 75%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Wilmette, IL
- Average rainfall in September: 3.11"
The wettest month (with the highest rainfall) is June (4.49").
The driest month (with the least rainfall) is December (1.38").
Average rainfall days in September
Wilmette, IL
- Average rainfall days in September: 14.9 days
The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is February (5.6 days).
Average snowfall in September
Wilmette, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Wilmette, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.6 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
Wilmette, 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: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Wilmette, IL
- Average sunshine days in September: 13 days
The month with the most sunshine days is December (15.3 days).
The months with the least sunshine days are June and July (10.9 days).
Average UV index in September
Wilmette, IL
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Wilmette, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and August (Cloud cover 27).
Average visibility in September
Wilmette, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
