A heat wave grips southern Ontario, bringing scorching daytime temperatures and muggy, restless nights. The week kicks off with blazing sunshine, warm breezes, and rising humidity that makes the air feel even heavier. These conditions are currently impacting most of southern Ontario, including major urban centres like Toronto, Hamilton, Mississauga, and Ottawa.
Sunday, June 22: cloud cover and oppressive heat
Today, Sunday, June 22, skies will be mostly cloudy across the region, with a 30% chance of late-afternoon showers. Daytime highs will climb to a sweltering 34 °C (93 °F), but with the high humidity, it will feel closer to 45 °C (113 °F). Winds will blow at 30 km/h, gusting up to 50 km/h, intensifying the sensation of heat.
By evening, skies will begin to clear, but the heat will linger, with overnight lows remaining near 22 °C (72 °F)—well above seasonal averages and signaling a tropical night.
Monday, June 23: blistering sun and extreme temperatures
Monday will start off mainly cloudy, but skies will clear through the afternoon as temperatures surge to 35 °C (95 °F), with a humidex reading around 43 °C (109 °F). The UV index will be very high at 10, marking dangerous levels of sun exposure.
Overnight, skies will stay clear, winds will ease, and the temperature will drop slightly to a warm 23 °C (73 °F)—another hot and humid night ahead.
Tuesday, June 24: sun, cloud and a risk of rain
Tuesday will feature a mix of sun and clouds, with a 30% chance of rain. The daytime high will once again reach 34 °C (93 °F). By night, cloudy breaks will continue with a lingering chance of showers, and the temperature will dip to 19 °C (66 °F).
Wednesday, June 25: more clouds, slightly cooler
On Wednesday, cloudy skies will persist, with a 30% chance of scattered showers through the day. Temperatures will be slightly more moderate, with highs of 28 °C (82 °F). In the evening, skies will remain overcast with the possibility of more rain, and the overnight low is expected to hold near 19 °C (66 °F).
Thursday, June 26: damp and overcast
Thursday will be mostly cloudy, with a 60% chance of rain as highs climb to 27 °C (81 °F). Rain is expected to continue into the night, along with overcast conditions, and the low will settle at 17 °C (63 °F).
Friday, June 27: unsettled with cooler air
Friday remains unsettled, with more cloud cover and another 60% chance of precipitation. Temperatures will be noticeably cooler, with highs of 23 °C (73 °F). In the evening, a few lingering showers may continue under cloudy skies, with overnight lows around 16 °C (61 °F).
Saturday, June 28: brief relief but lingering humidity
Saturday will bring a mix of sun and clouds, with a more comfortable high of 24 °C (75 °F). Interestingly, instead of cooling off, evening temperatures will rise slightly to 25 °C (77 °F), with the humidex pushing the perceived temperature to 32 °C (90 °F).
