Temperatures are expected to reach 12 C in Toronto by Friday. (Canadian Press)

Mild weather helped break a 27-year-old temperature record in Toronto on Thursday.

Just after 4:30 p.m. ET, temperatures at Pearson Airport reached 7.5 C, breaking a high of 7.4 C set back in 1984. Records were broken in other areas of southcentral Ontario.

"It's not uncommon to have yo-yoing temperatures in the spring," said CBC meteorologist Gina Ressler. "But the extent of the warmup today has been pretty remarkable."

Ressler said Toronto residents can expect more of the same overnight as temperatures are expected to hover in the 9 C range.

But Toronto residents should enjoy this winter warmup while it lasts because by Friday evening, forecasters are calling for a return to colder temperatures in the range of 3 C

Environment Canada had issued a special weather statement on Thursday for Toronto and many of the surrounding municipalities, warning commuters of possible freezing rain.

By mid-morning, two fatalities had been reported on roads in the region, along with a number of road closures. A total of 16 serious traffic accidents were reported on Thursday.

A woman died in a four-vehicle collision in Markham on McCowan Road at around 7:25 a.m. Another woman was killed two hours later in a multi-vehicle crash in Pickering, near Taunton Road and Brock Road.

The eastbound lanes of Highway 407 from Woodbine Avenue to McCowan Road reopened at around 9:45 a.m. after being closed for more than an hour because of ice-related crashes, according to Ontario Provincial Police. Earlier, the eastbound lanes of the Gardiner Expressway were closed due to a crash near Jarvis Street.

The roadway has since reopened, but traffic was heavy during the rush hour.

Transition period ahead

A low-pressure system moving into an area north of Toronto combined with an influx of warmer air from the Gulf of Mexico is the cause of Thursday's thaw, said CBC meteorologist Nick Czernkovich.

"I don't want to say we're getting into spring yet, but we're coming to that transition period," said Czernkovich. "So I think it's positive that we can start looking forward to these changes, where some days we get these warm-ups."

Temperatures are expected to hover around the 10 C mark overnight, before peaking at around 12 C Friday morning.

The record high for a Toronto Feb. 18, set in 1948, is 10.6 C.