Ontario’s weather still seems to be yo-yoing between wintery lows and summerlike highs, but the province’s 2025 summer forecast promises that higher temperatures will eventually stick around — but will they be too high?
While blustery frigid temperatures seem committed to sticking around until the bitter end (can it be now, please?), experts have been predicting above-average temperatures in Ontario this spring, which have already been foreshadowed by a handful of above-seasonal days so far.
This summer, they’re holding fast to that prediction, forecasting above-average — even potentially record-breaking — temperatures throughout the sunny season.
The Old Farmer’s Almanac’s summer 2025 report for the U.S. and Canada reports a slow build-up to hotter temperatures this summer, with June temperatures remaining more or less the same.
However, the Almanac predicts July and August will bring above-average temperatures to much of North America, and, with last spring and summer in Ontario seeing several temperature records smashed, this year’s weather could likely usurp even those.
The Almanac’s 12-month long-range forecast for Southern Ontario suggests that Toronto and GTA residents should prepare for the hottest periods of the year to hit during much of June and July, as well as mid- to late-August.
Additionally, the report’s temperature and precipitation outlook also predicts that August’s temperature and precipitation will show the greatest divergence from seasonal averages.
Environment and Climate Change Canada.
Environment and Climate Change Canada’s (ECCC) 4 to 6-month outlook for June, July and August is currently estimating an 85 per cent probability for above-average temperatures in Toronto (82 in Ottawa and 65 in Thunder Bay), with precipitation levels currently shaping up to be about average during that period.
Looking even further ahead into September, October and November, ECCC anticipates a 60 per cent probability of above-average temperatures in Toronto, on top of 64 per cent in Ottawa and 46 per cent in Thunder Bay, during that period — so we might be able to see quite the extended summer, much like last year.
In an earlier interview with blogTO, ECCC meteorologist Gerald Cheng explained that these probability models are calculated through a simulated climate model, which is run 20 times.
So, while these predictions are based on some fairly solid math, there’s no shortage of factors that can throw weather and climate systems off. In other words, we just might not know until we know!
In the meantime, get stocking up on sunscreen, water bottles and fans, because you’re going to need them this summer, Ontario.
