In September, Derry typically sees daytime highs of 15.7°C and overnight lows around 8.9°C. Compared to the annual average high of 11.9°C, September runs +3.8°C.
September in Derry averages a daytime high of 15.7°C and an overnight low of 8.9°C.
September runs +3.8°C compared to Derry's annual average high of 11.9°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 15.7°C and cooler evenings around 8.9°C.