Jefferson County (Fairfield)
September
Weather in Jefferson County, Iowa for September 2026
Your guide to Jefferson County weather in September - trends and predictions
So far, September 2026 in Jefferson County shows a warmer trend than usual by 2.2 °F.
Expect cooler weather in the next days in Jefferson County with the forecast suggesting a temperature of 26 °F, lower than the historical average.
In general, the average temperature in Jefferson County at the beginning of September is 28 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 24.9 °F by the end of September.
With an average of 5 rainy days, Jefferson County experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
25
Dry days
5
Rainy days
0
Snow days
26°/14°
Temperatures
17 km/h
Avg max wind
71 %
Avg humidity
Jefferson County Weather September
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Temperatures trend during September in Jefferson County
See the weather trend as well as the moving average line
September weather in Jefferson County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Mist | 31° /18° | 0 mm | 7 | |
| Sept. 2 |  Cloudy | 30° /17° | 0 mm | 7 | |
| Sept. 3 |  Moderate or heavy rain shower | 28° /18° | 31 mm | 6 | |
| Sept. 4 | Mist | 29° /14° | 0 mm | 7 | |
| Sept. 5 |  Overcast | 28° /17° | 0 mm | 7 | |
| Sept. 6 | Cloudy | 25° /14° | 0 mm | 6 | |
| Sept. 7 |  Sunny | 25° /11° | 0.1 mm | 4 | |
| Sept. 8 | Overcast | 29° /15° | 0 mm | 5 | |
| Sept. 9 | Cloudy | 26° /17° | 24.6 mm | 4 | |
| Sept. 10 |  Light rain shower | 26° /16° | 1.8 mm | 5 | |
| Sept. 11 | Fog | 29° /14° | 0 mm | 7 | |
| Sept. 12 | Overcast | 30° /17° | 0 mm | 7 | |
| Sept. 13 |  Partly cloudy | 28° /17° | 2.5 mm | 5 | |
| Sept. 14 |  Thundery outbreaks possible | 29° /17° | 0.4 mm | 5 | |
| Sept. 15 | Thundery outbreaks possible | 29° /20° | 5.7 mm | 4 | |
| Sept. 16 | Light rain shower | 20° /15° | 9.8 mm | 3.3 | |
| Sept. 17 | Light rain shower | 30° /19° | 3.5 mm | 4.2 | |
| Sept. 18 | Sunny | 34° /21° | 5.8 mm | 5.3 | |
| Sept. 19 | Light rain shower | 32° /22° | 13.6 mm | 4.4 | |
| Sept. 20 | Patchy rain possible | 27° /21° | 11.8 mm | 7 | |
| Sept. 21 | Light rain shower | 24° /17° | 5.5 mm | 6 | |
| Sept. 22 | Sunny | 23° /15° | 0 mm | 6 | |
| Sept. 23 | Patchy rain possible | 28° /17° | 11.2 mm | 7 | |
| Sept. 24 | Sunny | 18° /11° | 1.1 mm | 5 | |
| Sept. 25 | Sunny | 20° /9° | 0 mm | 5 | |
| Sept. 26 | Sunny | 24° /11° | 0 mm | 6 | |
| Sept. 27 | Overcast | 28° /15° | 0 mm | 6 | |
| Sept. 28 | Sunny | 30° /17° | 0 mm | 8 | |
| Sept. 29 | Overcast | 26° /16° | 3.5 mm | 5 | |
| Sept. 30 | Overcast | 28° /15° | 0 mm | 6 | |
| Next | |||||
Important Notice
Our weather forecast for Jefferson 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 Jefferson County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Jefferson County in September - FAQ
What are the expected maximum and minimum temperatures in Jefferson 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 Jefferson County during September?
Significant rainfall exceeding 112.3 mm is expected in Jefferson County during September, occurring over more than 5 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Jefferson County during September?
The average wind speed in Jefferson County during September is 17 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Jefferson County
Explore the daily rainfall trends and prepare for Jefferson Countys September weather 💧
Typically, Jefferson County has 5 rainy days in September with a total of 112.3 mm of rainfall.
UV exposure in Jefferson County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Jefferson County?Get accurate weather forecasts for Jefferson County, located at latitude 41.009 and longitude -91.963. Stay updated with localized weather information tailored for Jefferson County.
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