Residents of Quebec and Manitoba can expect a sweltering start to the weekend as Environment Canada warns of extreme heat and humidity in parts of the country. The weather advisory posted on Saturday says southern Quebec can expect temperatures over 30 C and a humidex of around 40 from Sunday afternoon through Tuesday. “It will be particularly uncomfortable at night,” the weather advisory warns, with temperatures remaining higher than 20 C. Areas in southern Manitoba are under a similar warning for Saturday, with humidex values of around 38 in the afternoon. “Conditions are expected to improve with the passage of a cold front overnight Saturday night,” Environment Canada says. Health Canada has issued an advisory for how to protect yourself from the health effects of extreme heat. Meanwhile, warnings of severe thunderstorms “capable of producing nickel to ping pong ball size hail” have been issued for parts of Ontario. The weather advisory also warns of winds gusting 90 km/hand heavy rains. Impacted areas include Cat Lake, Casummit Lake, Birch Lake, Whitestone Lake, Kapikik Lake, Gitche Lake, Maxim Lake, McCoy Lake, Nikip Lake and Senia Lake. Air Quality Warnings Environment Canada continues to issue air quality warnings for regions in Manitoba, Ontario, Quebec, Saskatchewan and the Northwest Territories. Wildfire smoke is causing poor air quality and reduced visibility in these areas through the weekend, the weather alert says. “Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour,” it reads. Residents are advised to avoid outdoor activities, reschedule or cancel outdoor events, keep their doors and windows closed and use a respirator-type mask like a NIOSH-certified N95 or equivalent to reduce exposure to smoke. More information about the effects of wildfire smoke can be found here.