The temperature may feel like 40 degrees this Tuesday afternoon, as heat warnings remain in effect across much of Ontario.

Environment and Climate Change Canada (ECCC) has renewed its heat warnings for a range of areas to the south like Windsor, to the east as far as Ottawa, and to the north up to Fort Hope, Ontario, on Tuesday morning.

In the Toronto area, maximum temperatures may reach between 29 to 34 degrees Celsius, while humidity may make it feel like 40 degrees.

The Climate Change agency stated that these types of temperatures are "unusual" for early September, and that heat and humidity can lead to deteriorating air quality.

The agency warned that "the risks are greater for young children, pregnant women, seniors, and individuals with chronic illnesses, as well as for those who work or exercise outdoors, so caution should be taken against the effects of heat-related illnesses: swelling, rashes, cramps, fainting, heat exhaustion, heat stroke, and the exacerbation of some health conditions."

To avoid overheating, the agency recommends staying in a cool place if possible, drinking plenty of water, and checking on older family members, friends, and neighbors; outdoor workers should also take scheduled breaks regularly. The agency noted that individuals or pets should not be left inside parked vehicles.

The Toronto District School Board says it has a plan in place to help its school communities cope with the high temperatures as children return to classrooms on the first day of school this Tuesday.

According to the school board, the plan includes reducing strenuous activities such as gym and sports, encouraging everyone to drink plenty of water, keeping doors and windows open where possible, and using fans to provide air circulation.

Of the 583 schools under the board's jurisdiction, 177 schools are largely air-conditioned, while another 243 have cooling centers in large spaces like gymnasiums or libraries. The remainder has cooling areas where classrooms can rotate, with temporary air conditioning units installed.