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
The transition into September subtly indicates a reduction in the average high-temperature, down to a still warm 73.8°F (23.2°C) from August's moderately hot 80.1°F (26.7°C). Throughout the nights in September, an average low-temperature of 57°F (13.9°C) is noted.Humidity
In September, the average relative humidity is 77%.Rainfall
In September, the rain falls for 12.2 days. Throughout September, 1.38" (35mm) of precipitation is accumulated. Throughout the year, there are 132.2 rainfall days, and 16.22" (412mm) of precipitation is accumulated.Snowfall
In Naperville, snow does not fall in May through September.Daylight
In Naperville, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:19 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:35 pm CDT.
Sunshine
In Naperville, the average sunshine in September is 8.8h.UV index
In Naperville, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: In September, a daily UV index of 4 turns into the following recommendations:
Take necessary precautions - Defending against sun damage is advocated. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Naperville have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Naperville have in September?
What is the UV index intensity in September?
Average temperature in September
Naperville, IL
- Average high temperature in September: 73.8°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28.4°F).
- Average low temperature in September: 57°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).
Average pressure in September
Naperville, 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
Naperville, 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 (6mph).
Average humidity in September
Naperville, IL
- Average humidity in September: 77%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Naperville, IL
- Average rainfall in September: 1.38"
The wettest month (with the highest rainfall) is May (2.09").
The driest month (with the least rainfall) is December (0.71").
Average rainfall days in September
Naperville, IL
- Average rainfall days in September: 12.2 days
The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Naperville, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.85").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Naperville, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Naperville, 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 5min
The months with the most sunshine are July and August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Naperville, IL
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is July (10.2 days).
Average UV index in September
Naperville, IL
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Naperville, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 31).
Average visibility in September
Naperville, 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).
Naperville, Illinois, USA
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