In September, Hemel Hempstead typically sees daytime highs of 17.9°C and overnight lows around 10.0°C. Compared to the annual average high of 13.1°C, September runs +4.8°C.
September in Hemel Hempstead averages a daytime high of 17.9°C and an overnight low of 10.0°C.
September runs +4.8°C compared to Hemel Hempstead's annual average high of 13.1°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 17.9°C and cooler evenings around 10.0°C.