A heat wave is usually defined as a period of 3 or more consecutive days with temperatures of 32° C or higher. High HUMIDITY is not a requisite, yet most, but not the worst, heat waves are oppressively humid. By these criteria St John's and Vancouver have never experienced a heat wave, and Victoria has had only one, lasting 4 days in 1941.
http://www.thecanadianencyclopedia.com/ ... heat-wave/
http://climate.weather.gc.ca/climate_da ... 1&Month=7#