My "Cool" summer clothing has a different feel to my other warm stuff- and checking the labels- they are made of 100% polyester. They are definitely only to be worn on their own on the hottest of days.

And I once made a mistake and bought a pair of Bib Shorts made in "Cool Max" material. Wrongly named their material as it is more like "Freeze Max". That stuff is cold on even on the hottest of days.

And never had any of my clothing shrink- even though I would like to think it has in the spring- but that is just the Chest slip down to the waist line.