Johnson County (Iowa City)
September
Weather in Johnson County, Iowa for September 2027
Your guide to Johnson County weather in September - trends and predictions
In general, the average temperature in Johnson County at the beginning of September is 26.8 °C. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 23.8 °C by the end of September.
Johnson County experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 248 mm.
Is September a good time to visit Johnson County? check out the best time to travel to Johnson County page.
✨ Is September a good time to visit Johnson County? – Ask the AI Weatherman
Temperatures
Rain 🌧️
More
23
Dry days
7
Rainy days
0
Snow days
26°/14°
Temperatures
17 km/h
Avg max wind
72 %
Avg humidity
Johnson County Weather September
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Temperatures trend during September in Johnson County
See the weather trend as well as the moving average line
September weather in Johnson County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /17° | 0 mm | 7 | |
| Sept. 2 | Sunny | 28° /15° | 0.1 mm | 5 | |
| Sept. 3 |  Moderate rain | 27° /15° | 10.4 mm | 6 | |
| Sept. 4 | Sunny | 28° /13° | 0 mm | 7 | |
| Sept. 5 |  Partly cloudy | 29° /16° | 0 mm | 6 | |
| Sept. 6 |  Overcast | 23° /12° | 0.1 mm | 4 | |
| Sept. 7 | Sunny | 23° /10° | 0 mm | 4 | |
| Sept. 8 | Overcast | 27° /11° | 0 mm | 4 | |
| Sept. 9 |  Heavy rain | 27° /14° | 136.7 mm | 5 | |
| Sept. 10 | Sunny | 27° /15° | 0 mm | 6 | |
| Sept. 11 | Sunny | 29° /14° | 0 mm | 7 | |
| Sept. 12 | Sunny | 29° /15° | 0 mm | 7 | |
| Sept. 13 |  Patchy rain possible | 27° /17° | 1.7 mm | 5 | |
| Sept. 14 | Partly cloudy | 29° /16° | 0.8 mm | 6 | |
| Sept. 15 |  Light rain | 28° /19° | 9.4 mm | 5 | |
| Sept. 16 | Light rain | 27° /16° | 4.6 mm | 5 | |
| Sept. 17 | Light rain | 29° /16° | 6.3 mm | 6 | |
| Sept. 18 | Patchy rain possible | 27° /16° | 1.7 mm | 5 | |
| Sept. 19 | Moderate rain | 27° /18° | 24.5 mm | 4 | |
| Sept. 20 | Heavy rain | 22° /16° | 27.6 mm | 4 | |
| Sept. 21 | Patchy rain possible | 23° /16° | 0.6 mm | 5 | |
| Sept. 22 | Light rain | 21° /14° | 8.3 mm | 4 | |
| Sept. 23 | Partly cloudy | 21° /11° | 0.4 mm | 5 | |
| Sept. 24 | Overcast | 20° /13° | 0.4 mm | 4 | |
| Sept. 25 | Light rain | 21° /11° | 3 mm | 4 | |
| Sept. 26 | Sunny | 24° /11° | 0.8 mm | 5 | |
| Sept. 27 | Partly cloudy | 25° /12° | 0.3 mm | 5 | |
| Sept. 28 | Sunny | 26° /14° | 0 mm | 5.5 | |
| Sept. 29 | Sunny | 27° /13° | 0.2 mm | 5 | |
| Sept. 30 | Moderate rain | 25° /15° | 10.1 mm | 4 | |
| Next | |||||
Important Notice
Our weather forecast for Johnson County 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 Johnson County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Johnson County in September - FAQ
What are the expected maximum and minimum temperatures in Johnson County during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 14°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Johnson County during September?
Significant rainfall exceeding 248 mm is expected in Johnson County during September, occurring over more than 7 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Johnson County during September?
The average wind speed in Johnson County during September is 17 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Johnson County
Explore the daily rainfall trends and prepare for Johnson Countys September weather 💧
Typically, Johnson County has 7 rainy days in September with a total of 248 mm of rainfall.
UV exposure in Johnson County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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