Environment Canada has extended heat warnings for Hamilton and the GTA.

It says maximum temperatures in Hamilton are expected to be near 30 C, with humidex values expected to reach near 40 C.

The meteorological agency says relief from the humidity and cooler temperatures are expected on Tuesday.

Environment Canada is warning that hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index to approach the high risk category. It says to watch for effects of health illness such as swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.

Everyone should drink plenty of water even before they feel thirsty and stay in a cool place. The agency is also urging people to check on older family, friends, neighbours and never to leave people or pets inside a parked vehicle.