The biggest indicators that someone is potentially suffering from heat exhaustion after being out in the sun for a while or in a space where they are unable to escape the heat include suffering from a headache, nausea, and feeling dizzy. Some other symptoms that can confirm that you need to remove yourself or whoever is experiencing these symptoms from the heat include: - A body temperature anywhere between 100˚ and 104˚ Fahrenheit - Increased sweating - Irritability - Muscle cramping - Skin that feels clammy and cold - Vomiting - Goose bumps - Fainting It cannot always be easy to know exactly if your child is displaying these symptoms, so it is highly recommended that you regularly check-in with them while spending time outside on a hot day to make sure that they are staying hydrated and are taking plenty of breaks by going indoors to cool off. Any signs of heat exhaustion means that the body needs to be cooled down as soon as possible to avoid developing into heat stroke, which will be much more dangerous.