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
September reveals a small adjustment in temperature, transitioning from an average high of 81.1°F (27.3°C) in August to a still moderately hot 74.3°F (23.5°C). Throughout the September nights, Clarendon Hills encounters a low-temperature of 57.9°F (14.4°C).Humidity
In Clarendon Hills, Illinois, the average relative humidity in September is 75%.Rainfall
In Clarendon Hills, in September, during 11.5 rainfall days, 1.18" (30mm) of precipitation is typically accumulated. Throughout the year, in Clarendon Hills, there are 118.5 rainfall days, and 13.74" (349mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:18 am and sunset at 7:24 pm. On the last day of September, in Clarendon Hills, Illinois, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In Clarendon Hills, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. 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
What is the usual temperature for Clarendon Hills in September?
What is the average humidity in September in Clarendon Hills?
How many days does it rain in September in Clarendon Hills?
When it does not snow in Clarendon Hills?
Does it snow in Clarendon Hills in September?
What is the average length of the day in September in Clarendon Hills?
When are sunrise and sunset in September in Clarendon Hills?
How long on average sun shines in September in Clarendon Hills?
How high is the UV index in September in Clarendon Hills?
Average temperature in September
Clarendon Hills, IL
- Average high temperature in September: 74.3°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 57.9°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).
Average pressure in September
Clarendon Hills, 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
Clarendon Hills, IL
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in September
Clarendon Hills, 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
Clarendon Hills, IL
- Average rainfall in September: 1.18"
The wettest month (with the highest rainfall) is May (1.97").
The driest month (with the least rainfall) is December (0.63").
Average rainfall days in September
Clarendon Hills, IL
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (4.2 days).
Average snowfall in September
Clarendon Hills, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Clarendon Hills, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Clarendon Hills, 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 4min
The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Clarendon Hills, IL
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in September
Clarendon Hills, 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 January (UV index 1).
Average cloud cover in September
Clarendon Hills, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Clarendon Hills, 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).
Clarendon Hills, Illinois, USA
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