If any of your strays are really friendly and dont mind being touched, what I do with mine are in the really hot weather i'll take a wet paper towel with cool water and just rub them down with it, it quickly cools them off especially when the ears are wet. They need shelter out of the sun but this cools them off quickly and they usually enjoy it, especially longhair cats or dark colored cats that have the sun heat them up the quickest.
Just thought id share that.
Just thought id share that.