If you are a master gardener you must be aware of climate zones. In the north, many trees are planted going into fall. It’s really not that hot this time of year. Plus, anyone with a clue would be watering that tree on a regular basis.
As far as planting a tree in the winter, I’ll give you a shovel when it is 30 below zero and see how far down you can dig. :)
Hah! wipes a bead of sweat from his forewhead...