Environment Canada Issues Heat Warning for Ontario, Eastern Canada as Temperatures to Soar to 45 Degrees

The Toronto skyline is shown on June 21, 2018. THE CANADIAN PRESS/ Tijana Martin

Environment Canada has issued an extreme heat advisory, predicting “dangerously hot and humid conditions” for parts of Ontario, Quebec, and New Brunswick throughout most of the week.

Southern, central, and northeastern Ontario can expect to see the thermometer creeping above the 30-degree mark beginning today with the humidex hitting 40 degrees or more June 18 through June 20, according to Environment Canada.

Daytime highs are forecasted to range from 30 to 35 degrees, with the humidity making it feel as hot as 45 degrees in Windsor, London, Toronto, Kingston, and the surrounding areas. Ottawa temperatures will be slightly lower with the humidity index at up to 40 degrees while much of Northeastern Ontario will see the humidex creep up to 42 degrees.

“There will be little relief through the overnight as lows are expected to be 18 to 23 degrees Celsius with humidex values of 26 to 30,” Environment Canada said in its advisory for southern Ontario. “Hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index approaching the high risk category.”

The northeastern part of the province as far north as Fort Albany can expect to be only slightly cooler overnight with temperatures of 17 to 20 degrees and humidity index hovering in the 25 to 30 degree range.

Environment Canada has also issued a heat warning for much of southern Quebec with the humidex exceeding 40 degrees in the afternoon beginning June 18. Daily highs between 30 and 35 degrees and overnight lows above 20 degrees are expected from Gatineau east to Montreal.

Sherbrooke and Trois-Rivières will be only slightly cooler with daytime highs between 30 and 34 degrees.

The agency is forecasting the hot air will move eastward as the week progresses with the hottest temperatures hitting New Brunswick June 19 and 20. Temperatures will soar as high as 30 to 33 degrees with the humidity making it feel as hot as 44 degrees in Fredericton.

While the humidity is expected to ease in Quebec and New Brunswick June 21, it will remain hot in Ontario.

Humidity in Southern and Central Ontario will remain well above 30 degrees through next week while some areas like Windsor will have the humidity hover around 40 degrees over the weekend.

The worst of the humidity will depart the northeastern parts of the province later this week with the humidex dropping below 30 degrees in Sudbury by June 21 while Sault Ste. Marie will cool off to 23 degrees by June 20.

Heat Safety

Extreme heat can be especially dangerous for older adults, young children, pregnant women, and people working outdoors. Health Canada recommends drinking plenty of water before feeling thirsty to decrease risk of dehydration.

It is also important to watch for the effects of heat illness, the agency said.

High body temperature, skin rash, muscle cramps, nausea or vomiting, heavy sweating, headache, rapid breathing and heartbeat, extreme thirst, and dark urine are all signs of heat exhaustion.

Anyone experiencing these symptoms during extreme heat should “immediately move to a cool place and drink liquids; water is best,” Health Canada says.

If confusion and lack of coordination, dizziness/fainting, and very hot, red skin with no sweating are also present, that is a sign of heat stroke, the agency said, adding that the condition should be treated immediately by a medical professional.