In May, Boston typically sees daytime highs of 20.3°C and overnight lows around 7.8°C. Compared to the annual average high of 15.0°C, May runs +5.3°C.
May in Boston averages a daytime high of 20.3°C and an overnight low of 7.8°C.
May runs +5.3°C compared to Boston's annual average high of 15.0°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 20.3°C and cooler evenings around 7.8°C.