In September, Swansea typically sees daytime highs of 16.5°C and overnight lows around 11.1°C. Compared to the annual average high of 12.3°C, September runs +4.2°C.
September in Swansea averages a daytime high of 16.5°C and an overnight low of 11.1°C.
September runs +4.2°C compared to Swansea's annual average high of 12.3°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 16.5°C and cooler evenings around 11.1°C.