Central and southern Ontario and much of western Quebec are forecast to experience another day of sweltering weather. Environment Canada’s heat warnings say daytime highs are expected to hit 30 to 35 C, with the humidex making it feel closer to 40. And while the daytime hours are expected to be steamy, there may be some relief during the overnights. The agency says the lows can vary between 18 to 23 C. However, any benefit from the roughly 10-degree difference could very well be lost when factoring in humidex values of 26 to 30.