Sun hoodies are made of a poly blend that is white, reflects a lot of sun, and is rated to keep you from getting burned through clothes which can happen with regular cotton or linen if you’re in the full sun all day. I’ve worn them all day in full sun and never get burned or even tanned on my shoulders.

Amazon and Alibaba sell them for like 20-50 euros. I like getting ones with thumb holes, a hood, and is at least 1-2 sizes too big because they are better when they drape and let the air in, and they are hard to remove when soaked in sweat.

They’ll be rated like UPF 50+ which just indicates high resistance. You want higher than 30+ at least.

The brand I’ve used for the last few years also makes them with a hood that has a built in lower face cover / balaclava. This is much warmer but very handy at keeping off the sun. I don’t use that kind, but I’ll use a high UPF white Buff neck gaiter to go over my lower face or forehead to hold the hood on. YMMV.

I’ll also use a wide brimmed floppy hat that will at least cover my upper face and nose, and I’ll wear sunscreen to an all day sun event on my hands and face. Otherwise I burn fast and it’s very unhealthy for skin aging and cancer risk.