In September, Heidelberg typically sees daytime highs of 20.4°C and overnight lows around 10.1°C. Compared to the annual average high of 14.2°C, September runs +6.2°C.
September in Heidelberg averages a daytime high of 20.4°C and an overnight low of 10.1°C.
September runs +6.2°C compared to Heidelberg's annual average high of 14.2°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 20.4°C and cooler evenings around 10.1°C.