The heat wave in on for Southern Quebec and Ontario, and where i am sitting (Montreal) it is already 33C in the shade with 65% humidity. Sticky and hot. However, you cannot keep kids indoors all the time, they will want to go out. Few precautions are necessary to keep them and self cool. There is a great article with plenty of tips published by yoyomama. Very useful tips, with plenty of details, given by Dr. Brown, a naturopathic doctor, and Dr. Peacock, a pediatrician. In a nutshell, here they are:
The signs of heat illness to watch out can include fatigue, thirst, red flushed cheeks, cool damp skin and muscle cramps. If left untreated it can progress to heat stroke which can result in dizziness, headaches, confusion and nausea and requires immediate medical attention.
Stay cool and play it cool.
July will be hot, hot, hot.