If the coop doesn't have big windows that shine sunlight into it - it would be cooler. If sun hits it, I imagine it is going to be hot.Okay well i'm going to disagree there, first of all it wont be shinning in the coop at all and second if you think about it when you dig in the sand it's cooler underneath and chickens like to take dust baths in it so I think it would be good and everyone who i've seen talking about sand in the coop says it's cooler in the summer.