Also, a black t shirt underneath the jacket, and thick black socks.
It's 100 degrees Fahrenheit, sunny and cloudless. And you wear all those clothes. You even walk onto a sandy public beach like that (shoes and all). And black attracts sunlight.
At least you won't get a sunburn, as you're not showing any skin, apart from your face and hands. Your feet won't burn in that sand either. Right?