On a personal basis, I don't move plants in the heat of summer. When it's 100 degrees out, they are much too stressed as it is, trying to deal with heat, rain (or lack thereof), pressure from insects, etc.
I have many plants that need to be moved but I am going to wait until our temperatures moderate, which will be late fall/early winter months. I just don't feel safe moving plants in the dead of summer, but that's just me.
If it's a case of "have to", I will pot them up and set them in the shade until time to safely plant.
