A Heat Warning has been issued for Windsor-Essex and Chatham-Kent.
Environment Canada says hot and humid air will push the temperature above 30 degrees throughout the Canada Day long weekend.
Combined with the humidity, Meteorologist Peter Kimball says it could feel like 40-degrees Celsius for the next three to five days.
Kimball tells AM800 News a warm air mass from the Midwest is driving the heat into the region.
"That's going to bring temperatures up above 30 and our heat warning threshold is 31 for a high and a low of 21," notes Kimball. "We might actually be a little below that for a couple of days over the weekend, but regardless it's going to be warm."
Kimball points out it's actually unusual to have the first heat alert of the season so late in June.
"Windsor gets about 5.5 days of 30-plus degree temperatures in June," says Kimball. "So having temperatures above 30 is actually nothing out of the ordinary. That said, our threshold for a heat warning is a high of 31 and a low of 21 for at least a couple of days."
Kimball adds it has been cooler in June so far.
"We've only had one 30-plus day so far this June and as I said, normally we have 5 and a half, so we're catching up basically, we're 2.5 degrees below normal so far," points out Kimball. "It's been cool up to now, so we're playing catch up."
Very warm and humid air, with higher than average temperatures may persist well into next week.
The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.
The Windsor-Essex County Health Unit suggests you drink plenty of water even before you feel thirsty and stay in a cool place. never leave people or pets inside a parked vehicle.