Heat and humidity ramps up in southwestern Ontario

Kitchener's Victoria Park in the summer of 2026. (Dan Lauckner/CTV News)

Muggy is the only word to describe the weather in Waterloo Region.

And, according to Environment Canada, the high heat and humidity will continue until at least Friday.

Wednesday’s forecast shows a high of 27 degrees Celsius, but it will feel closer to 35 with the humidex. The agency also predicts cloudy conditions with a 40 per cent chance of rain in the morning and early afternoon, with a thunderstorm risk in the afternoon.

As of 8 a.m., the mercury was sitting at 21.8 degrees Celsius. Environment Canada also noted 97 per cent humidity, making it feel like 30 degrees Celsius.

Further south, a heat warning was issued for Windsor, Chatham-Kent, Sarnia and Grand Bend. The agency says those areas could see daytime highs closer to 31 degrees Celsius, with humidex values between 36 and 40. The heat event is expected to continue Thursday but could linger into Friday or even Saturday.

Thursday’s forecast could be a repeat of Wednesday, with a 40 per cent chance of rain in the morning and temperatures climbing to 28 degrees Celsius but feeling like 36.

Southern Ontario should get a break from the humidity starting Friday.

Environment Canada predicts a 60 per cent chance of showers and a high of 26 degrees Celsius, dropping to a low of 15 degrees Celsius overnight.

Over the weekend, there’s a chance for more rain and temperatures in the mid-20s.

Monday and Tuesday will be slightly cooler and closer to 20 degrees Celsius.