Humidex to reach 44 degrees Celsius today.
A heat warning is in effect for Niagara.
Environment Canada says the region can expect hot and humid conditions today and tomorrow.
The weather office says today's high will reach 32 degrees, but the humidex will make it feel like 44.
Tonight's overnight low will be 24 degrees, providing little relief from the heat.
The agency is forecasting a high of 32 and a humidex of 41 tomorrow.
Slightly cooler temperatures are expected on Thursday.
Environment Canada is reminding you not to leave pets or kids inside a parked car.
You're also advised to keep an eye out for the effect of heat illness, which include swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.