In September, Harlingen typically sees daytime highs of 32.7°C and overnight lows around 22.7°C. Compared to the annual average high of 28.5°C, September runs +4.2°C.
September in Harlingen averages a daytime high of 32.7°C and an overnight low of 22.7°C.
September runs +4.2°C compared to Harlingen's annual average high of 28.5°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 32.7°C and cooler evenings around 22.7°C.