Ontario’s weeks-long dry streak continues, tropical moisture may lurk
Toronto hasn’t seen measurable rainfall since Sept. 16
Many communities across southern Ontario are in the midst of their longest dry streaks of 2026.
Expect this rain-free spell to continue for a while longer, potentially matching or besting the 16 consecutive dry days Toronto experienced in 2025.
Signs of change lurk on the horizon heading into the end of next week as Hurricane Polo eventually pushes inland.
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Several weeks without measurable precipitation
Conditions for most of September have been a welcome reprieve for southern Ontario after a damp, stormy, and rainy summer throughout the region.
Persistent centres of high pressure over the Great Lakes have deflected most opportunities for precipitation; in fact, southern Ontario hasn’t seen a drop of rain since Sept. 16. We have to look back to the end of May to find the last equivalent dry streak.
An average September produces about 69 mm of rain at Toronto-Pearson Airport. This month has only recorded 48.1 mm of rain, almost all of which fell during the severe thunderstorms on Sept. 2.
Such a spell of dry weather isn’t terribly unusual for this time of year. Last September saw 16 dry days, and the airport went 21 consecutive days without precipitation in Sept. 2017.
Why do these calmer, drier stretches always seem to occur in September? This transition month sees summer trying to hold on while autumn tries its best to sweep away the old season. This is often accompanied by high-pressure systems over the Great Lakes, which in turn bring calm and sunny conditions.
Pattern likely prevails through the end of September
The forecast remains dry and sunny for the remainder of this weekend and into the final days of September, all but guaranteeing that the region will pad its dry stretch.
Hurricane Polo may throw a curveball toward Ontario by the end of this upcoming week.
A surge of moisture, potentially including Polo’s remnants, will move into the U.S. Southwest and trek across the continent by the first weekend of October. This may bring southern Ontario its first real opportunity for rain since the middle of September.