In May, Joliet typically sees daytime highs of 22.1°C and overnight lows around 9.2°C. Compared to the annual average high of 15.3°C, May runs +6.7°C.
May in Joliet averages a daytime high of 22.1°C and an overnight low of 9.2°C.
May runs +6.7°C compared to Joliet's annual average high of 15.3°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 22.1°C and cooler evenings around 9.2°C.