A heat warning is in effect for the Niagara Region and much of Southern Ontario.
Environment Canada says an increasingly humid airmass will continue streaming into the region from the south.
Temperatures today will be in the low 30's, but the humidex will make it feel like nearly 40 degrees.
Relief appears to be on the way Tuesday.
Two cooling centres will be available in Niagara Falls today from 11 a.m. until 3 p.m. one is at the Gale Centre the other the Victoria Avenue public library.
Splash pads also opened in most areas this weekend.