Saint Louis County (Eureka)
September
Weather in Saint Louis County, Missouri for September 2026
Your guide to Saint Louis County weather in September - trends and predictions
So far, September 2026 in Saint Louis County shows a warmer trend than usual by 4.2 °F.
Expect cooler weather in the next days in Saint Louis County with the forecast suggesting a temperature of 23.5 °F, lower than the historical average.
In general, the average temperature in Saint Louis County at the beginning of September is 30.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.9 °F by the end of September.
The climate of Saint Louis County in September is notably wet, with an average of 11 rainy days, and a total of 324.5 mm of precipitation.
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Temperatures
Rain 🌧️
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19
Dry days
11
Rainy days
0
Snow days
28°/17°
Temperatures
12 km/h
Avg max wind
64 %
Avg humidity
Saint Louis County Weather September
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Temperatures trend during September in Saint Louis County
See the weather trend as well as the moving average line
September weather in Saint Louis County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Fog | 33° /19° | 0 mm | 7 | |
| Sept. 2 |  Sunny | 33° /19° | 0 mm | 8 | |
| Sept. 3 |  Overcast | 31° /18° | 0 mm | 7 | |
| Sept. 4 | Sunny | 32° /18° | 4.8 mm | 7 | |
| Sept. 5 |  Partly cloudy | 31° /18° | 0 mm | 7 | |
| Sept. 6 |  Patchy rain possible | 29° /18° | 9.4 mm | 6 | |
| Sept. 7 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 8 | Sunny | 30° /11° | 0 mm | 7 | |
| Sept. 9 | Sunny | 29° /14° | 1.5 mm | 7 | |
| Sept. 10 | Sunny | 29° /16° | 21.1 mm | 5 | |
| Sept. 11 | Partly cloudy | 31° /19° | 0.7 mm | 6 | |
| Sept. 12 | Sunny | 32° /19° | 0 mm | 8 | |
| Sept. 13 | Patchy rain possible | 30° /20° | 1.5 mm | 6 | |
| Sept. 14 | Mist | 31° /18° | 0 mm | 7 | |
| Sept. 15 | Light rain shower | 32° /21° | 1.2 mm | 7 | |
| Sept. 16 | Partly cloudy | 32° /20° | 1.7 mm | 6 | |
| Sept. 17 |  Cloudy | 32° /20° | 1 mm | 7 | |
| Sept. 18 | Sunny | 33° /19° | 0 mm | 7 | |
| Sept. 19 | Sunny | 34° /20° | 1.3 mm | 7 | |
| Sept. 20 | Overcast | 33° /22° | 0 mm | 6.8 | |
| Sept. 21 | Patchy rain possible | 24° /17° | 9.2 mm | 3.5 | |
| Sept. 22 | Overcast | 22° /15° | 0.1 mm | 3.9 | |
| Sept. 23 | Sunny | 24° /13° | 0 mm | 6.7 | |
| Sept. 24 | Overcast | 24° /13° | 0 mm | 6.9 | |
| Sept. 25 | Overcast | 24° /14° | 0 mm | 5 | |
| Sept. 26 | Overcast | 18° /15° | 0 mm | 5 | |
| Sept. 27 | Overcast | 25° /15° | 0 mm | 6 | |
| Sept. 28 | Sunny | 26° /14° | 0 mm | 7 | |
| Sept. 29 | Sunny | 28° /16° | 1.9 mm | 7 | |
| Sept. 30 | Light rain shower | 22° /15° | 7.6 mm | 5 | |
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Important Notice
Our weather forecast for Saint Louis 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 Saint Louis County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Saint Louis County in September - FAQ
What are the expected maximum and minimum temperatures in Saint Louis County during September?
During September, expect a variety of temperatures with highs around 28° and lows near 17°, suitable for diverse activities and preferences.
How much rainfall should be expected in Saint Louis County during September?
Significant rainfall exceeding 324.5 mm is expected in Saint Louis County during September, occurring over more than 11 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Saint Louis County during September?
The average wind speed in Saint Louis County during September is 12 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Saint Louis County
Explore the daily rainfall trends and prepare for Saint Louis Countys September weather 💧
Typically, Saint Louis County has 11 rainy days in September with a total of 324.5 mm of rainfall.
UV exposure in Saint Louis County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Saint Louis County?Get accurate weather forecasts for Saint Louis County, located at latitude 38.503 and longitude -90.628. Stay updated with localized weather information tailored for Saint Louis County.
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