Environment Canada has issued a heat warning for North Bay, Powassan, Mattawa, West Nipissing  and French River.

Humidex values reaching 40 are expected.

A heat event is setting up for the Canada Day long weekend.

Beginning Friday and extending through to Sunday, southwest winds will bring hot and humid air from the Gulf of Mexico.

Daytime high temperatures in the low thirties are forecast, with humidex values in the mid to high thirties.

Low temperatures overnight are expected to be in the high teens to low 20s providing little relief from the heat.

Slightly cooler conditions will likely arrive late Sunday into Monday morning as a cold front is expected to move through the region.

Extreme heat affects everyone.

The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.

Watch for the effects of heat illness: swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.

Filed under: environment-canada, heat-warning