In July, Saint Charles typically sees daytime highs of 31.6°C and overnight lows around 19.4°C. Compared to the annual average high of 18.7°C, July runs +12.9°C.
July in Saint Charles averages a daytime high of 31.6°C and an overnight low of 19.4°C.
July runs +12.9°C compared to Saint Charles's annual average high of 18.7°C, ranking #1 of 12 months by warmth.
Plan for daytime highs near 31.6°C and cooler evenings around 19.4°C.