In September, Sioux Falls typically sees daytime highs of 23.3°C and overnight lows around 9.1°C. Compared to the annual average high of 13.7°C, September runs +9.5°C.
September in Sioux Falls averages a daytime high of 23.3°C and an overnight low of 9.1°C.
September runs +9.5°C compared to Sioux Falls's annual average high of 13.7°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 23.3°C and cooler evenings around 9.1°C.