Caution is being urged as a heat warning's been issued for the Chapleau and Gogama areas.
Environment Canada says daytime temperatures today and tomorrow will near 30 degrees - with humidex values in the mid- to upper-30s - considered the first "heat event" of the season, expected to ease as a slow moving cold front brings rain on Thursday.
Public Health Sudbury and Districts warn the heat can lead to heat stroke, heat exhaustion, fainting, heat rash, heat cramps, and more issues, with older adults, young children, pregnant women, people with chronic illnesses, alcohol or drug users, the homeless, and those working or exercising in the heat most at risk.
To deal with the heat, the health unit recommends wearing loose-fitting light-coloured clothing made of breathable fabric, drinking plenty of liquids, seeking shade, and taking breaks from the heat.