Child oveheat issues. What can i do

So my almost 4year old son logan tends to overheat even in cooler weather.
I noticed during summer when he was about 7months old and all he was sitting in his stroller.

At first i always thought it was sunburn as he turns bright red. But once i got him inside and he relaxes a bit he turns back to his normal color.

So during the summer months a lot i have to watch him. If he is starting to get red i sit him down in shade and give him ice cold water and or popsicle. If he doesnt get to normal color with that i have to bring him back in which he gets mad about. I always put sunblock on him as well to prevent sunburn.
What else can i do to help him from overheating. And why does he overheat. Haiden my oldest never has and vince is starting to.
See logan and vince have red tint in their hair which seems to attract the sun and the heat, where as haiden is more of a light light brown.

    We live in AZ and its hard to keep Lucas cool when we go outside. We do the same things you do! In addition though, we usually have a cooler with us, and we keep a wet rag in there. So the rag stays super cool and if he needs it, we give him a super cool rub down. It feels really great in the heat and works for him. Maybe give that a try? :)
    About Ashley
    Birth: March 23
    On since: Mar 6, 2014
    I am 25year old stay at home mom of 3boys. I am also married.