In September, Appleton typically sees daytime highs of 21.6°C and overnight lows around 9.3°C. Compared to the annual average high of 12.5°C, September runs +9.1°C.
September in Appleton averages a daytime high of 21.6°C and an overnight low of 9.3°C.
September runs +9.1°C compared to Appleton's annual average high of 12.5°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 21.6°C and cooler evenings around 9.3°C.