Weather in Naperville, Illinois for September 2026
Flood Watch - See hour by hour.
So far, September 2026 in Naperville is slightly warmer than the historical average by 1.2 °F.
Expect cooler weather in the next days in Naperville with the forecast suggesting a temperature of 17.4 °F, lower than the historical average.
In general, the average temperature in Naperville at the beginning of September is 28 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 19.6 °F by the end of September.
The climate of Naperville in September is notably wet, with an average of 11 rainy days, and a total of 102.7 mm of precipitation.
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Naperville Weather September
Temperatures trend during September in Naperville
September weather in Naperville day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /16° | 0.6 mm | 6 | |
| Sept. 2 | Sunny | 29° /17° | 0 mm | 7 | |
| Sept. 3 | Sunny | 31° /16° | 12.8 mm | 7 | |
| Sept. 4 |  Mist | 30° /16° | 0 mm | 7 | |
| Sept. 5 |  Overcast | 28° /17° | 0.6 mm | 7 | |
| Sept. 6 |  Patchy rain possible | 25° /14° | 2.4 mm | 6 | |
| Sept. 7 | Sunny | 24° /11° | 0 mm | 6 | |
| Sept. 8 | Overcast | 25° /11° | 0 mm | 5 | |
| Sept. 9 | Mist | 25° /13° | 9.8 mm | 5 | |
| Sept. 10 | Sunny | 28° /14° | 0 mm | 6 | |
| Sept. 11 | Sunny | 28° /15° | 10.6 mm | 7 | |
| Sept. 12 | Mist | 27° /14° | 0 mm | 6 | |
| Sept. 13 | Mist | 25° /15° | 0.4 mm | 5 | |
| Sept. 14 | Mist | 27° /15° | 0 mm | 7 | |
| Sept. 15 |  Cloudy | 29° /17° | 3 mm | 6 | |
| Sept. 16 | Sunny | 28° /16° | 1.2 mm | 6 | |
| Sept. 17 |  Light rain | 26° /16° | 4.9 mm | 5 | |
| Sept. 18 | Fog | 27° /14° | 0.9 mm | 5 | |
| Sept. 19 | Light rain shower | 26° /15° | 14.4 mm | 5 | |
| Sept. 20 | Light rain shower | 20° /15° | 91.5 mm | 0.5 | |
| Sept. 21 | Overcast | 16° /14° | 0 mm | 2.4 | |
| Sept. 22 | Patchy rain possible | 15° /12° | 0.8 mm | 1.7 | |
| Sept. 23 | Patchy rain possible | 16° /13° | 0.2 mm | 2.3 | |
| Sept. 24 | Overcast | 19° /13° | 0 mm | 5.3 | |
| Sept. 25 | Overcast | 19° /13° | 0 mm | 5 | |
| Sept. 26 | Overcast | 16° /14° | 0 mm | 4 | |
| Sept. 27 | Overcast | 20° /15° | 0 mm | 5 | |
| Sept. 28 | Sunny | 22° /13° | 0 mm | 6 | |
| Sept. 29 | Sunny | 21° /12° | 0 mm | 6 | |
| Sept. 30 | Light rain shower | 20° /12° | 3.4 mm | 4 | |
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Naperville in September - FAQ
What are the expected maximum and minimum temperatures in Naperville during September?
How much rainfall should be expected in Naperville during September?
What are the typical wind conditions in Naperville during September?
September rainfall patterns in Naperville
UV exposure in Naperville during September
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Where is Naperville?Get accurate weather forecasts for Naperville, located at latitude 41.786 and longitude -88.147. Stay updated with localized weather information tailored for Naperville.