Environment Canada has issued a heat warning for Windsor-Essex, Leamington, Chatham-Kent and Rondeau Park.
Hot and humid temperatures will make their way through the region from the mid-western United States Sunday and will linger into Tuesday.
Daytime highs are expected to hit 31C but will feel like 40C with the humidity. Overnight temperatures in the low '20s are not expected to provide much relief.
Residents should be mindful of young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors, according to Environment Canada.
Pets should also be kept in the shade and provided with plenty of water if they must be outside.