Did Sioux Falls Just Have a Record-Breaking September for Rain?

September certainly gave Sioux Falls plenty of rain, but did the month actually set a rainfall record?

According to the National Weather Service, Sioux Falls finished September 2026 with 5.79 inches of precipitation.

That's a significant amount of rain compared with the September normal of 2.73 inches...more than three inches above average.

However, despite the soggy conditions, September 2026 did not set the record for the wettest September in Sioux Falls.

The record remains 9.3 inches, recorded in September 1986.

Other notably wet Septembers include 2016, when Sioux Falls received about 7.6 inches, and 2018, which brought about 7.3 inches.

September 2026 did have several stretches of substantial rainfall.

By September 27, the National Weather Service was reporting 5.39 inches for the month, already more than double the normal precipitation for September.

Rain continued late in the month, including 0.40 inches on September 29.

Top 10 Wettest Months in Sioux Falls History

1. June 2014 — 13.70 inches
2. June 2024 — 11.20 inches
3. August 1932 — 9.33 inches
4. September 1986 — 9.26 inches
5. May 1936 — 9.03 inches
6. July 2010 — 8.60 inches
7. June 1984 — 8.40 inches
8. July 1992 — 8.40 inches
9. May 1993 — 8.30 inches
10. August 2002 — 8.30 inches

So while September 2026 wasn't the wettest September Sioux Falls has ever seen, it was considerably wetter than normal.

And after a summer that included plenty of hot and dry days, September certainly reminded Sioux Falls residents that fall can bring some much needed precipitation.