Toronto will feel more like mid-July than mid-September on Thursday, with forecasters calling for a high of 28 °C and a humidex near 33, making it one of the warmest days of the month.
Environment Canada says skies will be mostly sunny, with light winds. The heat will be amplified by humidity levels, pushing the “feels-like” temperature into the low 30s — conditions more typical of peak summer than the early days of fall.
Historically, Toronto’s average daytime high for mid-September is around 22 °C, according to long-term climate data. This means Thursday’s forecast is roughly six degrees above normal, and the humidex will make it feel more than 10 degrees warmer than the seasonal average.
September in Toronto often brings a gradual cooling trend, with average highs dipping toward the high teens by month’s end. But this week’s late-season heat surge is bucking that pattern, offering residents an extended taste of summer.
Cooler air on the way
The warmth won’t last, much to the dismay of those expecting a hot and humid weekend. A cold front is expected to sweep through southern Ontario late Friday, ushering in cooler, drier air for the weekend. By Saturday, Toronto’s forecast high is just 19 °C — a drop of nearly 10 degrees from Thursday’s peak.
Sunny skies are expected to accompany the cooler temperatures, making for a crisp and comfortable start to the weekend.
Overnight lows will also trend downward, dipping into the low-to-mid teens, with temperatures dropping to single digits on Friday night (9 °C).
What’s next
Sunday’s daytime high in Toronto could perk back up to the mid-20s, with a forecasted high of 24 °C and a mix of sun and clouds. Showers could move in by nightfall, with a 30 per cent chance of rain in the city, but it will be slightly warmer than usual overnight (15 °C).
Forecasters say the cooldown will be short-lived, with temperatures expected to rebound slightly early next week. Though always subject to change, rain is forecast for Monday and Tuesday, with daytime highs of 25 °C and 24 °C in Toronto.
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