Extended Heat Warning for Hamilton effective June 24, 2025

HAMILTON, ON – The Medical Officer of Health for the City of Hamilton has initiated an Extended Heat Warning beginning today.  The Extended Heat Warning stays in effect until a cancellation notice is sent.

A prolonged heat event continues through Friday or Saturday.  Dangerously hot and humid conditions are expected. Daytime highs are expected to be 30°C to 35°C with humidex values of 40°C to 45°C. There will be little relief through the overnight as lows are expected to be 20°C to 23°C with humidex values of 26°C to 30°C. Temperatures and humidex values may be several degrees cooler near the shores of the Great Lakes. 

Hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index approaching the high risk category.

The City of Hamilton and participating community agencies are responding to the heat by offering “cool places” to go during all stages of a heat event. These locations can be identified by a “Cool Down Here” sign at the entrance. 

As part of the heat response plan regularly scheduled Open Swims at all City of Hamilton indoor pools will be free of charge. There are many spray pads, additional cool places and outdoor pools across Hamilton. 

For more information visit www.hamilton.ca/heat