In September, Casper typically sees daytime highs of 24.1°C and overnight lows around 5.9°C. Compared to the annual average high of 15.2°C, September runs +8.9°C.
September in Casper averages a daytime high of 24.1°C and an overnight low of 5.9°C.
September runs +8.9°C compared to Casper's annual average high of 15.2°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 24.1°C and cooler evenings around 5.9°C.