Why do materials that are poor heat conductors cool to temperatures less than the surrounding air?
The poor heat conductor isn’t actually cooler than the air around it. It just seems that way because it is able to pick up and retain the heat around it and is doing so efficiently enough to feel cool. Look up the concepts of latent heat in a thermodynamics book and the concepts of Bronian movement in a chemistry book to understand how energy is absorbed at molecular levels.
