In May, Thornton typically sees daytime highs of 22.4°C and overnight lows around 6.3°C. Compared to the annual average high of 18.6°C, May runs +3.8°C.
May in Thornton averages a daytime high of 22.4°C and an overnight low of 6.3°C.
May runs +3.8°C compared to Thornton's annual average high of 18.6°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 22.4°C and cooler evenings around 6.3°C.