Heat warning in effect for Southwestern Ontario

Environment Canada has issued a heat warning for much of southern Ontario, from Windsor through to Peterborough and Ottawa.

The agency says temperatures are expected to remain high, and nighttime lows will provide little relief from the heat.

In Windsor, it's expected to reach at least 33 C Monday. For London the high will be 32 C and feel like 37 C, with lows near 22 C.

Environment Canada says Toronto's temperatures are expected to peak at 31 C Sunday, and 32 C Monday, with lows near 21 C.

And in Ottawa, highs are expected to be about the same as those in Toronto, with lows near 20 C.

Environment Canada is warning people to watch out for the effects of heat-related illness, including swelling, rash, cramps, fainting and the worsening of some health conditions.

It says people should drink plenty of water, even before starting to feel thirsty, and seek a cool place.

It's also reminding people not to leave pets in parked cars.