Hot and sticky weather prompts warnings from Saskatchewan to Quebec

Oppressive heat expected across 4 provinces, Environment Canada warns

Potentially hazardous temperatures forecast in much of Manitoba, most of Ontario

What's behind the wild weather in Canada this summer?

Environment Canada's warning maps from the southeastern corner of Saskatchewan to the western edges of Quebec are evocative of flames, yellow and orange — which should feel about right this week, as four provinces sizzle under temperatures that will feel like mid-40s C with the humidity.

Southern and central parts of Manitoba and almost all of Ontario including Toronto and Ottawa are under heat warnings, with the weather agency warning of high humidity, heat exhaustion and, in some places, bad air.

Yellow alerts denote hazardous weather that "may cause" disruption or health impacts, while orange alerts are "likely to" cause them. The orange warnings on Monday stretch from slightly south of Regina eastward through Winnipeg until the Quebec border.

Temperatures in the 30s are expected throughout the warning areas, including a high of 38 C in Thunder Bay, Ont.

In Saskatchewan, Manitoba, and northwestern Ontario, the heat is expected to peak today, while in the other regions under warning it will be hotter Tuesday. Records have already fallen in Manitoba, where seven communities set new temperature records Sunday including Portage la Prairie, which beat a record set during the Second World War with a temperature of 35.7 C.

Environment Canada says the impending hot and humid air could cause air quality, already recently tainted by wildfire smoke, to once again deteriorate.

The City of Toronto says water and cooling stations, as well as pools, beaches and splash pads, will be available to the public. Winnipeg's leisure centres and libraries are similarly open as cooling areas.

Check online for cooling centres in your region.

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Environment Canada says people should be on the lookout for signs of heat exhaustion, which include headaches, dizziness, thirst and fatigue. Anyone who is showing signs of heat stroke should call 911.

Older adults, people living alone and other at-risk people should be checked on multiple times a day, the warning says.

Other tips from Environment Canada:

Is this weather normal? Track climate changes in your area here.

With files from The Canadian Press and CBC Ottawa, Toronto and Manitoba