In October, Saint Charles typically sees daytime highs of 20.8°C and overnight lows around 7.4°C. Compared to the annual average high of 18.7°C, October runs +2.1°C.
October in Saint Charles averages a daytime high of 20.8°C and an overnight low of 7.4°C.
October runs +2.1°C compared to Saint Charles's annual average high of 18.7°C, ranking #6 of 12 months by warmth.
Plan for daytime highs near 20.8°C and cooler evenings around 7.4°C.