In September, Richland typically sees daytime highs of 27.1°C and overnight lows around 10.1°C. Compared to the annual average high of 18.7°C, September runs +8.5°C.
September in Richland averages a daytime high of 27.1°C and an overnight low of 10.1°C.
September runs +8.5°C compared to Richland's annual average high of 18.7°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 27.1°C and cooler evenings around 10.1°C.