That also depends a lot on the surface. A really smooth (possibly even dark) porcelain stoneware surface gets hotter than a rough concrete slab. Our granite windowsills are hotter than the paved surface in the driveway. A smooth plastic surface gets very, very hot in the sun. Just go to a large building materials store, they also have WPC outside in the display, and walk barefoot over it.
Best regards
Sabine