Waterloo (IA)
September
Weather in Waterloo, Iowa for September 2025
Your guide to Waterloo weather in September - trends and predictions
In general, the average temperature in Waterloo at the beginning of September is 23.3 °F. As the month progressed, temperatures tended to noticeably warm up, reaching an average of 25.6 °F by the end of September.
Waterloo experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 62.9 mm.
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Temperatures
Rain 🌧️
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24
Dry days
6
Rainy days
0
Snow days
26°/13°
Temperatures
19 km/h
Avg max wind
63 %
Avg humidity
Waterloo Weather September
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Temperatures trend during September in Waterloo
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September weather in Waterloo day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 22° /13° | 0 mm | 6 | |
| Sept. 2 | Sunny | 23° /9° | 0 mm | 6 | |
| Sept. 3 | Sunny | 24° /11° | 0 mm | 6 | |
| Sept. 4 | Sunny | 26° /11° | 0 mm | 7 | |
| Sept. 5 |  Patchy rain possible | 27° /15° | 0.1 mm | 6 | |
| Sept. 6 | Patchy rain possible | 21° /12° | 0.1 mm | 5 | |
| Sept. 7 | Sunny | 20° /7° | 0 mm | 6 | |
| Sept. 8 | Sunny | 24° /8° | 0 mm | 6 | |
| Sept. 9 | Sunny | 28° /12° | 0 mm | 7 | |
| Sept. 10 | Sunny | 28° /14° | 0 mm | 7 | |
| Sept. 11 | Sunny | 30° /14° | 0 mm | 8 | |
| Sept. 12 | Sunny | 29° /17° | 0 mm | 7 | |
| Sept. 13 |  Overcast | 27° /16° | 0.1 mm | 6 | |
| Sept. 14 | Patchy rain possible | 28° /17° | 0.7 mm | 6 | |
| Sept. 15 | Patchy rain possible | 30° /19° | 0.3 mm | 7 | |
| Sept. 16 |  Partly cloudy | 30° /18° | 0 mm | 7 | |
| Sept. 17 | Overcast | 27° /16° | 0 mm | 6 | |
| Sept. 18 |  Cloudy | 29° /16° | 0 mm | 6 | |
| Sept. 19 |  Heavy rain at times | 30° /18° | 12.5 mm | 7 | |
| Sept. 20 | Overcast | 28° /19° | 37.6 mm | 6 | |
| Sept. 21 | Patchy rain possible | 30° /17° | 7.5 mm | 7 | |
| Sept. 22 |  Moderate or heavy rain shower | 19° /13° | 3.7 mm | 4 | |
| Sept. 23 | Patchy rain possible | 21° /6° | 0.1 mm | 5 | |
| Sept. 24 | Patchy rain possible | 21° /11° | 0.2 mm | 5 | |
| Sept. 25 | Sunny | 25° /10° | 0 mm | 7 | |
| Sept. 26 | Overcast | 26° /12° | 0 mm | 6 | |
| Sept. 27 | Sunny | 26° /11° | 0 mm | 7 | |
| Sept. 28 | Overcast | 28° /13° | 0 mm | 6 | |
| Sept. 29 | Overcast | 27° /13° | 0 mm | 6 | |
| Sept. 30 |  Mist | 26° /12° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Waterloo in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Waterloo forecast closer to your planned date for the most up-to-date weather information.
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Waterloo in September - FAQ
What are the expected maximum and minimum temperatures in Waterloo during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Waterloo during September?
Moderate rainfall is anticipated in Waterloo during September, with a total of 62.9 mm spread over approximately 6 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Waterloo during September?
The average wind speed in Waterloo during September is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Waterloo
Explore the daily rainfall trends and prepare for Waterloos September weather 💧
UV exposure in Waterloo during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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