It is expected to feel like 40 degrees across large parts of Ontario and Quebec as a heat wave continues.

Environment Canada is forecasting maximum temperatures in the low 30s, and a humidex around 40, as the agency warns of elevated risks for heat-related illnesses.

With overnight temperatures hovering around 20 degrees, offering little relief to the day's stuffy heat, Toronto extended outdoor pool hours to 11:45 p.m. Tuesday at seven locations.

Parts of northern Ontario are forecasted to get cooler conditions by Thursday.

But Environment Canada says the rest of the province will have to wait until Friday for the heat wave to pass.

The agency says the hot and humid air can also deteriorate air quality.

This report by The Canadian Press was first published July 5, 2023.