In September, Castle Rock typically sees daytime highs of 24.4°C and overnight lows around 7.0°C. Compared to the annual average high of 16.8°C, September runs +7.6°C.
September in Castle Rock averages a daytime high of 24.4°C and an overnight low of 7.0°C.
September runs +7.6°C compared to Castle Rock's annual average high of 16.8°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 24.4°C and cooler evenings around 7.0°C.