OTTAWA, July 14 (Xinhua) -- Canada's environment authority on Monday afternoon issued multiple heat warnings for several provinces, including Ontario, Quebec and the Atlantic provinces.

According to Environment Canada, the heat warnings cover big cities like Toronto, Ottawa and Montreal with daytime highs of up to 35 degrees Celsius, which, combined with high humidity, will feel like up to 42 degrees and are expected to continue to Thursday night.

"Southern Ontario will experience hot and humid conditions now through much of this week. A shift in the weather pattern late this week will likely end this multi-day period of heat and humidity Thursday night," said the authority.

"Extreme heat can affect everyone's health. Determine if you or others around you are at greater risk of heat illness. Check on older adults, those living alone and other at-risk people in-person or on the phone multiple times a day," Environment Canada cautioned. ■