BARRIE, ONT. -- It's a scorcher with temperatures soaring above 30 C on Tuesday.

Environment Canada has issued a heat warning for parts of southern Ontario, including several areas across the region.

Temperatures will continue to hit summer-like highs all week before shifting on Friday as a cold front moves in.

"Humidex values in the mid to upper 30s will prevail each afternoon," states the weather agency's website on Tuesday.

The local health unit is advising residents to stay hydrated, avoid over-exerting and stay out of the sun as much as possible until cooling centres can reopen.

"This is part of learning to live with COVID-19. That we find ways to have cooling centres that are run so that they're still safe," says Dr. Charles Gardner, Simcoe Muskoka District Health Unit medical officer of health.

The health unit's top doc saying the most vulnerable, like young children and seniors, should seek shelter from the heat while cooling stations remain closed during the pandemic.