In September, Saint Peters typically sees daytime highs of 30.4°C and overnight lows around 24.6°C. Compared to the annual average high of 29.2°C, September runs +1.2°C.
September in Saint Peters averages a daytime high of 30.4°C and an overnight low of 24.6°C.
September runs +1.2°C compared to Saint Peters's annual average high of 29.2°C, ranking #1 of 12 months by warmth.
Plan for daytime highs near 30.4°C and cooler evenings around 24.6°C.