A sweaty Saturday: Hottest day of the year in Toronto, Ottawa

The sweltering weather continues Saturday with several parts of Canada under heat warnings.

It's the hottest day of the year so far for Toronto, said Environment Canada meteorologist Sherry Williams, among other parts of southern Ontario.

The Greater Toronto Area has daytime highs of34 C, though it will feelmore like 44 with the humidex.

The evening might not bring much relief the overnight low will hover around 22, but it will still feel like over 30 throughout the night.

It should cool downthe GTAon Sunday, Environment Canada says, as humidity drops andtemperatures fall into the mid to high20s.

• Find all Environment Canada heat warnings here

There's hot and humid weatherin severalparts ofOntario, southern Quebec,Nova Scotia andNew Brunswick, the agency warns.

Southern Quebec and Ontario have temperatures in the 30s, with humidex values reaching the upper 40s farther south.

It's also the hottest day of summerso far for Ottawa and Windsor, said Williams, and it's likely the same for other places in southern Ontario.

As of 2 p.m.Ottawa was "winning" the heat contestin Ontario with a humidex of 46, Williams said.

But Ontario temperatures could still climb another few degreesby the end of the day, she said.

"I don't think these are record-breaking temps, but they're pretty close," said Williams. "And it's very widespread."

As of late Saturday afternoon, there werealso severe thunderstorm watches and warnings in several parts of southern Ontario andQuebec, as well as Fort Nelson, B.C., and parts of the Northwest Territories.

The huge blob of hot air that has blanketed several regions is known as a "heat dome." The heat was also strong on Friday, with the humidex as high as 42 in Toronto and reaching 47 in Sarnia.

Parts of northern Alberta andthe Northwest Territories are also underheatwarnings, with temperatures reaching 30 C.

Heat warnings different across country

The threshold for heat warnings changes in different parts of the country, said Williams.

Warnings are based on typical temperatures in each region and people's tolerance for hot weather, she said.

"Someone up in Timmins wouldn't be as used to the heat as someone in Windsor," Williams added.

It's been a hot couple of days for partsof Canada.

"When you go outside, you feel like you're in the water because it is so humid," said meteorologist Julie Deshaies, speaking to CBC Montreal earlier in the week.

In Nova Scotiaand New Brunswick, humidex values could be as high as 39 in parts of the province Saturday.

Environment Canada is reminding people to check in on loved ones, drink plenty of water and never leave people or pets in a parked vehicle.

The Ontario SPCAcalled on pet owners to take extra precautions over the next several days to keep their pets cool and safe.

The massive heat wave has also enveloped the U.S. Midwest and has pushed into the Northeast, ushering in temperatures that could top 38in Washington and prompting utilities to take steps to prevent power outages.