small children and high temperatures

Small children sometimes seem to be unaffected by high temperatures, whereas in fact they can have many problems dealing with it.

Don't put them in the sun, but at a place in the shadow or at a cool place, but not in the draft.

Dress them lightly, and put a towel or other absorbing fabric over anything plastic.

Give them plenty to drink.

These are just the three basic advices.
There are many more.