In September, Oshkosh typically sees daytime highs of 22.0°C and overnight lows around 9.8°C. Compared to the annual average high of 12.8°C, September runs +9.2°C.
September in Oshkosh averages a daytime high of 22.0°C and an overnight low of 9.8°C.
September runs +9.2°C compared to Oshkosh's annual average high of 12.8°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 22.0°C and cooler evenings around 9.8°C.