Weather in Brown County, South Dakota for September 2026
Until now, September 2026 in Brown County has been nearly identical to the historical average, with a temperature of 23.7 °F (showing only a slight deviation of 0.3 °F).
An exceptional deviation from the historical average is forecasted for next days of September 2026 in Brown County with the forecasted temperature being 16.7 °F, much lower than usual.
In general, the average temperature in Brown County at the beginning of September is 25.4 °F. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 23.3 °F by the end of September.
With an average of 3 rainy days, Brown County experiences minimal rainfall in September.
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Brown County Weather September
Temperatures trend during September in Brown County
September weather in Brown County day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Fog | 25° /13° | 0.5 mm | 3 | |
| Sept. 2 |  Thundery outbreaks possible | 29° /16° | 0.2 mm | 6 | |
| Sept. 3 |  Overcast | 27° /14° | 0 mm | 6 | |
| Sept. 4 | Overcast | 24° /10° | 0.1 mm | 5 | |
| Sept. 5 | Overcast | 24° /14° | 2.8 mm | 5 | |
| Sept. 6 | Overcast | 25° /14° | 1.2 mm | 6 | |
| Sept. 7 |  Sunny | 24° /12° | 8.5 mm | 4 | |
| Sept. 8 | Thundery outbreaks possible | 28° /15° | 0 mm | 6 | |
| Sept. 9 | Fog | 27° /15° | 0 mm | 6 | |
| Sept. 10 | Fog | 30° /12° | 0 mm | 6 | |
| Sept. 11 | Overcast | 28° /17° | 0 mm | 4 | |
| Sept. 12 |  Patchy light rain with thunder | 24° /14° | 10.4 mm | 4 | |
| Sept. 13 | Fog | 24° /15° | 0 mm | 4 | |
| Sept. 14 | Fog | 26° /16° | 6.7 mm | 3 | |
| Sept. 15 | Fog | 26° /13° | 0 mm | 6 | |
| Sept. 16 | Fog | 26° /12° | 0.2 mm | 4 | |
| Sept. 17 |  Moderate or heavy rain shower | 21° /14° | 11.5 mm | 1 | |
| Sept. 18 | Fog | 20° /15° | 11 mm | 1 | |
| Sept. 19 | Mist | 17° /14° | 0.4 mm | 1 | |
| Sept. 20 | Fog | 19° /13° | 0.5 mm | 2 | |
| Sept. 21 | Fog | 20° /11° | 0.6 mm | 3 | |
| Sept. 22 | Thundery outbreaks possible | 21° /10° | 0.1 mm | 4 | |
| Sept. 23 |  Partly cloudy | 22° /12° | 0.4 mm | 3 | |
| Sept. 24 | Fog | 22° /14° | 2.1 mm | 3 | |
| Sept. 25 | Mist | 23° /12° | 0.2 mm | 3 | |
| Sept. 26 | Mist | 24° /12° | 0.8 mm | 3 | |
| Sept. 27 | Sunny | 22° /12° | 0.9 mm | 4 | |
| Sept. 28 | Sunny | 24° /11° | 2.5 mm | 3 | |
| Sept. 29 | Sunny | 24° /16° | 5.4 mm | 2.5 | |
| Sept. 30 | Sunny | 24° /17° | 0 mm | 4.6 | |
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Brown County in September - FAQ
What are the expected maximum and minimum temperatures in Brown County during September?
How much rainfall should be expected in Brown County during September?
What are the typical wind conditions in Brown County during September?
September rainfall patterns in Brown County
UV exposure in Brown County during September
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Where is Brown County?Get accurate weather forecasts for Brown County, located at latitude 45.465 and longitude -98.486. Stay updated with localized weather information tailored for Brown County.