September weather forecastOak Lawn, IL
September
Weather in September
September rings the curtain down on summer, bringing a considerable reduction in temperature in Oak Lawn. The onset of fall can be felt with cooler weather and shorter days. Rainfall decreases, providing relief to those weary of the summer showers. Despite a decline in daylight, sunshine remains dominant, making days pleasant. With a tinge of Autumn, September offers a refreshing change in Oak Lawn.Temperature
The start of September comes with a small reduction in the average high-temperature, subtly receding from a warm 79.9°F (26.6°C) in August to a still moderately hot 73.6°F (23.1°C). September nights are marked by an average low-temperature of 59.2°F (15.1°C).Humidity
In September, the average relative humidity is 75%.Rainfall
In Oak Lawn, in September, it is raining for 13.5 days, with typically 1.97" (50mm) of accumulated precipitation. In Oak Lawn, during the entire year, the rain falls for 147.7 days and collects up to 23.62" (600mm) of precipitation.Snowfall
In Oak Lawn, snow does not fall in May through September.Daylight
In Oak Lawn, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:33 pm CDT.
Sunshine
The average sunshine in September in Oak Lawn is 9.1h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.Note: A maximum daily UV index of 4 during September morphs into the following directions:
Undertake precautions - Guarding against sun damage is counselled. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Oak Lawn, IL
- Average high temperature in September: 73.6°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in September: 59.2°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Oak Lawn, 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
Oak Lawn, IL
- Average wind speed in September: 7.7mph
The windiest month (with the highest average wind speed) is January (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Oak Lawn, IL
- Average humidity in September: 75%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Oak Lawn, IL
- Average rainfall in September: 1.97"
The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is December (1.02").
Average rainfall days in September
Oak Lawn, IL
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is July (18 days).
The month with the least rainy days is February (4.9 days).
Average snowfall in September
Oak Lawn, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.07").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Oak Lawn, 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 May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Oak Lawn, 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 6min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Oak Lawn, IL
- Average sunshine days in September: 13 days
The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is July (9.8 days).
Average UV index in September
Oak Lawn, 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
Oak Lawn, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Oak Lawn, 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).
