Why sunscreen quits before noon

Sunscreen works, until it does not. Most men put it on once in the morning, miss the back of the neck and the tops of the hands, then sweat it off before lunch. The guidance is to reapply every two hours, and more often after swimming. Almost nobody does.

Water makes it worse. A splash or a swim strips a good part of the layer, and the glare off the surface adds exposure on your arms and face. By early afternoon the skin that felt covered is bare again.

A UPF 50+ weave holds its rating in the water and keeps working for the whole day. Use both if you like, but let the shirt, the cap and the sleeves cover the skin that sunscreen always seems to miss.