Waterloo residents are in for another warm and sticky week, with temperatures in the mid-to-high 20s and elevated humidex values making it feel even hotter. While no heat warnings are currently in place, the muggy conditions are expected to persist into the start of August, according to Environment Canada.
This morning at the Region of Waterloo International Airport, it was already 22.2°C by 11 a.m., with 78 percent humidity driving the humidex up to 28. Tuesday’s forecast high of 26°C could feel closer to 33 once humidity is factored in. Wednesday will bring mainly sunny skies and a high of 24°C, but north winds of 30 km/h are expected to make it feel a touch cooler. The humidex is forecast to drop to 28 on Wednesday.
The warm trend continues through the balance of the week. Thursday and Friday are looking sunny with highs of 27°C and 28°C respectively. By Saturday, clouds return with a high of 26°C, and Sunday brings a 40 percent chance of showers and a cooler high of 22°C. Monday is expected to be a mix of sun and cloud and a high of 25°C.
This stretch of weather follows an eventful July for Waterloo Region. A heat warning was issued on July 13, when humidex values reached the low 40s. Earlier, during a late June heat wave, local paramedics responded to 14 to 14.5 percent more emergency calls compared to the same period in 2025, as a local news outlet reported. Severe thunderstorms also brought heavy rain and damaging winds on July 21.
The Weather Network’s 2026 summer forecast for Ontario predicted an inconsistent season, with heat interrupted by frequent showers and storms. So far, that mix has played out across the region.
