In September, McAllen typically sees daytime highs of 33.7°C and overnight lows around 22.1°C. Compared to the annual average high of 29.5°C, September runs +4.3°C.
September in McAllen averages a daytime high of 33.7°C and an overnight low of 22.1°C.
September runs +4.3°C compared to McAllen's annual average high of 29.5°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 33.7°C and cooler evenings around 22.1°C.