In September, Northampton typically sees daytime highs of 17.6°C and overnight lows around 9.4°C. Compared to the annual average high of 12.8°C, September runs +4.8°C.
September in Northampton averages a daytime high of 17.6°C and an overnight low of 9.4°C.
September runs +4.8°C compared to Northampton's annual average high of 12.8°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 17.6°C and cooler evenings around 9.4°C.