As long as I don't put them on too thick they don't heat up much, but most of the clippings this time were dry because the grass was mowed a couple of days before without a bagger and we just went over it to pick them up. It worked pretty good. I do like mulching for looks plus I cannot keep up with the weeding by myself and watering so it really helps.
We don't have a lot of leaves available but this fall we will search them out.