In May, Ottawa typically sees daytime highs of 19.0°C and overnight lows around 6.1°C. Compared to the annual average high of 11.1°C, May runs +7.9°C.
May in Ottawa averages a daytime high of 19.0°C and an overnight low of 6.1°C.
May runs +7.9°C compared to Ottawa's annual average high of 11.1°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 19.0°C and cooler evenings around 6.1°C.