Environment Canada issuing its first heat warning of the season.
North Niagara, including St. Catharines and Grimsby, is under a heat warning today with temperatures expected to hit a high of 32 degrees with a humidex near 39.
South Niagara, meanwhile, including Niagara Falls, Welland and Fort Erie, is under a special weather statement.
The weather office says temperatures will be slightly lower because Lake Erie is still fairly cool.
Temperatures in the southern tier are expected to reach 31 degrees today with a humidex near 36.
The Niagara Region has also issued a Heat Alert advising residents to schedule outdoor activities carefully, rest frequently in shady areas, and drink plenty of fluids.
Officials also remind residents never leave infants or young children in a parked car.
Dress them in cool, loose clothing, and shade their heads and faces with hats or an umbrella.
Ensure infants and children are protected with sunscreen.
People are also advised to consult a doctor if they feel signs of confusion, dizziness, nausea, muscle swelling, heart disturbances, and/or a headache.