In September, San Sebastian typically sees daytime highs of 22.1°C and overnight lows around 14.6°C. Compared to the annual average high of 17.1°C, September runs +5.0°C.
September in San Sebastian averages a daytime high of 22.1°C and an overnight low of 14.6°C.
September runs +5.0°C compared to San Sebastian's annual average high of 17.1°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 22.1°C and cooler evenings around 14.6°C.