OTTAWA, just after sunrise on Thursday, an intense heat event surges into Southern Ontario, blanketing Toronto, Mississauga, Brampton, Hamilton and the Niagara Region in sweltering air. Thermometers are poised to top 35 °C (95 °F) by mid-afternoon, while the oppressive humidex pushes perceived temperatures toward 44, turning city streets into shimmering corridors of warmth.
Forecasters anticipate the most blistering spell today, yet overnight relief remains elusive. After dark, readings may only slip to 20–23 °C (68–73 °F), maintaining a thick, sticky atmosphere that lingers over high-rise rooftops and leafy suburban crescents alike. By Friday daytime, actual highs should slide closer to 30 °C (86 °F), although the sultry humidex could still spike near 40, confirming another day of relentless mugginess.
Even as daytime peaks moderate moving into the weekend, forecasters underline the stubbornness of these elevated night-time lows. The air mass sprawled above Lake Ontario and the Golden Horseshoe shows little sign of budging, hinting that select pockets may endure the oppressive cloak of warmth straight through Saturday and Sunday.
Residents across Peel, Halton and Durham counties, along with commuters weaving along Highway 401 and skirting the QEW, wake to shimmering pavement and hazy horizons. Morning joggers in Centennial Park, beachgoers on Toronto Islands, and market-goers in St. Catharines all feel the heavy atmosphere settle like a wool blanket.
Throughout today and tomorrow, the sun’s glare ripples over Hamilton Harbour and dances above the roaring Escarpment highways. Cooling lake breezes will be limited, barely nudging the swelter aside. By tonight, starlight may flicker behind a thin veil of moisture, keeping nocturnal temperatures stubbornly warm across Niagara Falls and up through York Region.
Should the air mass stall, another bout of sultriness could stretch into the front end of next week, prolonging the sticky spell for Southern Ontario’s bustling cities, vineyard valleys and lakeside villages.
