Widespread rain arrived across much of southern Ontario late Wednesday night, with some lingering showers and thunderstorms possible through the day on Thursday. As the rain departs and conditions improve, it'll be the stifling mid-summer-like heat that will take centre stage across the region for the weekend and beyond. In fact, some places may end up seeing the earliest June heatwave on record, as daytime highs soar above 30°C. With the humidex, the feels like factor could be nearing 40 by next week. More on this extended blast of heat, below.
Visit our Complete Guide to Summer 2021 for an in-depth look at the Summer Forecast, tips to plan for it and much more!
THURSDAY INTO FRIDAY: LINGERING RAIN SHOWERS AND A SLIGHT THUNDERSTORM THREAT
Though a rare sight as of late, the system that moved into southern Ontario Wednesday night helped to bring some beneficial rains to the region through Thursday. While not overly excessive, the general amounts forecast in the 5-15 mm range will assist in the especially dry sections that saw very little rain during the month of May.
Some lingering showers and the chance of some non-severe thunderstorms are possible into Thursday afternoon, though most of the day will remain rain free across southern Ontario.
As a cold front moves through the region on Friday however, there's another chance for thunderstorms, though mainly focused on central and eastern parts of the province. The greatest amount of energy will be in eastern Ontario and southern Quebec, which could have the potential for thunderstorm to reach severe criteria.
WEEKEND AND BEYOND: EXTENDED HEATWAVE BEGINS AS TEMPERATURES SOAR
In the wake of this system, a ridge of high pressure will settle in above the province, allowing temperatures to begin a gradual climb back into decidedly summer-like territory.
This weekend will see a return to abundant sunshine and mid-summer heat, as temperatures near or exceed the 30-degree mark.
"The heatwave will continue into next week, with Monday, Tuesday and Wednesday being mostly sunny, hot and humid," says Dr. Doug Gillham, a meteorologist at The Weather Network. "High temperatures will reach at least the lower 30s with a humidex in the upper 30s to near 40."
EARLIEST JUNE HEATWAVE ON RECORD?
This stretch of extended heat could be some of the earliest on record for June. The last time the city of Toronto for example, saw five days of 30°C+ temperatures in June was back in 1949 on June 11-15. There was however, an even longer seven day stretch of extreme heat as early as May 14 in 1962.
Regardless, these sizzling temperatures so early in June will likely be record-setting and will help to tip the month as a whole to the above seasonal side.
Some relief from the heat and humidity is possible at the end of next week or on the weekend, though there is still some uncertainty as to exactly when the cold front will come through.
Precipitation-wise, it will be rain-free early and mid-next week, with just the chance of scattered thunderstorms. So it will become very dry across the region once again. The next potential for widespread showers and thunderstorms will be late week when the cold front finally approaches the region.
Stay tuned to The Weather Network for the latest on the incoming heat in Ontario.