KITCHENER -- Southwestern Ontario will experience summer-like weather over the next few days.

Environment Canada has issued a heat warning, saying temperatures will climb to the low-30s Tuesday, with increasing humidity Wednesday.

Humidex values in the mid- to high-30s are expected, with overnight lows near 20 degrees Celsius.

That will providing little relief from the extreme heat.

All areas between the GTA and Windsor are included in the agency’s heat warning.

During a heat warning, Environment Canada says the risks are greater for younger children, pregnant women, older adults, those with chronic illness and people working or exercising outdoors.

Temperatures are expected to cool off Wednesday night, following a risk of thunderstorms as Tropical Depression Cristobal approaches the province.

Strong winds and heavy rain are in the forecast with the potential for thunderstorm development.