In September, Karatsu typically sees daytime highs of 26.9°C and overnight lows around 20.6°C. Compared to the annual average high of 19.4°C, September runs +7.6°C.
September in Karatsu averages a daytime high of 26.9°C and an overnight low of 20.6°C.
September runs +7.6°C compared to Karatsu's annual average high of 19.4°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 26.9°C and cooler evenings around 20.6°C.