In May, Janesville typically sees daytime highs of 21.2°C and overnight lows around 8.3°C. Compared to the annual average high of 13.9°C, May runs +7.3°C.
May in Janesville averages a daytime high of 21.2°C and an overnight low of 8.3°C.
May runs +7.3°C compared to Janesville's annual average high of 13.9°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 21.2°C and cooler evenings around 8.3°C.