It’s going to be a scorcher in southern Ontario, with a heat warning in effect for much of the region.

Environment Canada says “significant heat and humidity” is expected to arrive Friday and continue Saturday with temperatures in the low to mid-thirties but will feel much higher.

The agency says some areas could experience their highest temperatures so far this year.

Local municipalities are warning residents about the extreme weather. The Medical Officer of Health in Hamilton has issued a heat warning.

Health officials warn extreme heat can cause heat cramps, heat exhaustion, heatstroke and death. Signs of heat exhaustion include heavy sweating, weakness, cold, pale and clammy skin, weak pulse, fainting, and vomiting. If experiencing symptoms, seek help right away – call 911 of needed. Residents should take precautions to reduce their risk of heat-related illnesses.

Free swimming is being offered at City of Hamilton indoor and outdoor pools.

Health officials suggest the following precautions to reduce your risk of heat-related illness.

• Drink plenty of water. Avoid drinking alcoholic and caffeinated beverages on hot days.
• Go to an air-conditioned place. Visit a cool place such as a mall, public recreation centres, public libraries, and other City-run air-conditioned facilities, etc.
• Dress to protect from the heat. Wear lightweight, loose-fitting, light-coloured clothing. Wear a hat or take an umbrella to keep your head cool and don’t forget sunscreen.
• Take it easy. Limit physical activities (walking, running, gardening, etc.) during the day. If rescheduling activities to dawn or dusk when it may be cooler, protect yourself with insect repellant as mosquitoes are more active at such times.
• Cool off. Take a cool bath or shower.
• Keep your living space cool. Close your blinds or curtains. Open windows to let air circulate when using a fan.
• Never leave children or pets alone in closed vehicles. Temperatures in a car can become life-threatening within minutes.
• Check on your neighbours and family.

Environment Canada says a cooler and less humid air mass will arrive in the wake of a weak cold front Sunday.