In September, Iowa City typically sees daytime highs of 24.6°C and overnight lows around 11.4°C. Compared to the annual average high of 15.4°C, September runs +9.2°C.
September in Iowa City averages a daytime high of 24.6°C and an overnight low of 11.4°C.
September runs +9.2°C compared to Iowa City's annual average high of 15.4°C, ranking #4 of 12 months by warmth.
Plan for daytime highs near 24.6°C and cooler evenings around 11.4°C.