Southern Ontario is in for one roller coaster of a shortened workweek, meteorologically speaking, as temperatures take a nosedive after literal months of hot, humid weather.

Today could actually be the coldest day we've experienced in Toronto since mid-June, according to the Weather Network, with plenty of gloom (read: clouds and drizzle) in the sky to boot.

"Tuesday's cooldown will be short-lived, with temperatures recovering on Wednesday to something more seasonal, though the chance of a more drastic warmup has faded," reads an update from the Weather Network published this morning.

"However, much cooler weather will win out across the whole region by the end of the week, with temperatures on the cool side of seasonal through next weekend." 

Environment Canada is calling for highs of no more than 20 C throughout the week: Just 17 C today and 19 C on Wednesday, Thursday and Saturday

Environment Canada forecast

Even more unsettling are the federal weather agency's forecasted overnight lows, particularly on Thursday and Friday.

Both evenings could see temperatures dip down to just 9 C, according to meteorologists, putting us well into "get your parka out" territory. But don't.

Like the Weather Network said, the pattern should be short-lived. By Saturday, overnight temperatures will be back up to a more seasonal 15 C.

Temperatures won't broach 20 C at all though this week, day or night, if Environment Canada is correct, and it'll be sopping wet outside for much of it (with the exceptions of Friday and Saturday, which, while slightly cooler than what we've become used to, should be nice and sunny.)

Potential heat waves are still on the horizon for later in the month, meaning that fall hasn't skipped us completely just yet — which is good, since it's technically still summer.