Weather warning issued for ‘prolonged period’ in southern Ontario

A weather warning issued Friday will extend for a “prolonged period” in southern Ontario.

Environment and Climate Change Canada issued a heat warning on Friday for much of southern Ontario, including the Greater Toronto Area.

Daytime highs of 29 to 32 C and a humidex of 35 to 40 C are expected to start today and continue into next week. The overnight lows will only reach 19 to 23 C, providing little relief from the heat, Environment Canada said in the warning.

“The temperatures and humidex will meet or be extremely close to heat warning criteria, with the hottest day being Saturday,” the warning stated. “A shift in the weather pattern on Thursday will likely end this multi-day period of heat and humidity.”

Extreme heat can affect everyone’s health, the warning said.

Check on older adults, those living alone and other at-risk people in-person or on the phone multiple times a day, Environment Canada suggested.

“Watch for the early signs of heat exhaustion in yourself and others. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue,” the warning said. “Stop your activity and drink water. Heat stroke is a medical emergency.”

Signs of heat stroke can include red and hot skin, dizziness, nausea, confusion and change in consciousness. If you suspect heat stroke, call 911 and while you wait for medical attention, try to cool the person by moving them to a cool place, removing extra clothing, applying cold water or ice packs around the body.

Other advice includes drinking water often, closing blinds or shades or opening windows if outside is cooler than inside. Turn on air conditioning, use a fan, or move to a cooler area of your living space.

Move to a cooling centre, community centre, library or shaded park if your home is too hot.

For more information, see How to protect yourself from the health effects of extreme heat.

Areas shaded in red are under a heat warning, possibly until Thursday.