I was in Spain for a vacay just last month in May where the temperatures went to 38 deg C on some days. I had only checked the weather forecast right before our flight and was mortified because I thought it would be spring
I ended up wearing several of the 90cm silks that I had packed as blouses on the days the temperatures went past 30 deg C, and I found them AMAZING in the heat because of how lightweight they were! I'm going to do it for every summer holiday destination in the future that doesn't require me to be covered up to respect local customs.
I had to slather on lots of sunscreen on my exposed skin, but I was careful not to touch my scarves and I think my husband was way more miserable in his cotton T-shirts than I was. With a fan in my hand, I survived all the hottest days
I wear a bandeau top under my scarves so I don't accidentally expose myself. I think it helps to take some of the yucky sweaty feeling away too. Once I got home, I hand-washed all my scarves with the Laundress Delicate Wash and they were as good as new thereafter! I would only worry about not getting stubborn stains like food or wine on the silk.
I enjoyed wearing them so much that I made a Reel on my IG on how to wear 90cm scarves as a blouse, for whoever is interested!