Residents in Waterloo Region got a taste of the humidity late last week but that will pale in comparison to what’s in store later this week.
The week kicked off with seasonal temperatures but the heat and humidity will move into the region starting on Tuesday and peak mid-to late-week, with humidex values in the high 30s to the low 40s.
“We’re back into the summer-like heat and humidity beginning Tuesday… it’s going to be feeling quite uncomfortable at times, especially by Wednesday, Thursday, as this humidity really starts to peak,” said CityNews meteorologist Jessie Uppal.
The high for Monday was 26 C but the temperature will start to rise on Tuesday with a high of 27 C, feeling closer to 35 C.
Uppal said Wednesday is expected to be very muggy as the mercury soars to a high of 28 C with a humidex of 36. It is expected to remain hot and sticky on Thursday with a high of 28 C and the highest humidex of the week.
With the humidity comes the return of wet weather. Uppal said this is especially the case for Tuesday as the forecast calls for isolated showers and a risk of thunderstorms that will linger on and off through the evening and overnight.
“Temperatures are actually going to be quite warm and uncomfortable, likely hovering between 18 to about 20 degrees Celsius. And that will continue Tuesday night, Wednesday night, and again, Thursday night. So very little in terms of relief from the hot, sticky conditions,” she said.
Uppal said there is also a chance for some on and off wet weather on Wednesday and Thursday with a risk of some isolated thunderstorms.
The humidity will ease off slightly by Friday evening but humidex values will still remain in the mid 30s for the start of FIFA World Cup 2026 in Toronto.
Although the official start of summer is later in June, Waterloo Region has already seen above seasonal temperatures this month.
Summer officially arrives at 4:24 a.m. ET on June 21.
