I have a four foot tall Maple tree in Utah, full sprouted leaves from Spring, when can I transplant it?

Someone said wait until next winter when the leaves haven't sprouted. Doesn't sound right to me. So, when is the best time to transplant it? In Utah, colder weather arrives at the end of October to close Fall season, warmer weather arrives in April, early Spring, with a rainy season, with trees starting to show buds and some sprouting. Month of May is warmer , Spring and trees are fully sprouted. Winter is December, January, February, March with snow. Summer is June, July, August, September and its very hot here with lots of sun and very little rain.I have a four foot tall Maple tree in Utah, full sprouted leaves from Spring, when can I transplant it?
You can get away with it in early spring but if it's already sprouted leaves it's needing a lot of energy right now to create the food it needs to sustain for the season. It could cause too much stress transplanting it. The best time is in early fall when trees start to go into dormancy. They are no longer using the energy to produce food for themselves. It will cause less shock on the plant and it will be able to focus on creating a strong rooting system in its new environment as it goes to sleep for the winter. As with any transplants, make sure it has plenty of water and it's best to do a transplant on an overcast day. The less sunlight a plant has during the first 24 hours of transplantation is best.I have a four foot tall Maple tree in Utah, full sprouted leaves from Spring, when can I transplant it?
Plant it now.I have a four foot tall Maple tree in Utah, full sprouted leaves from Spring, when can I transplant it?
I've seen it done in the fall season at businesses, but I think it would be better if done in early spring when the ground can be worked because the cool temps will give it time to settle before it starts getting hot. If it going to be done in the summer they should be watered often so the heat doesn't kill them during the transition. Build a trench around your tree to ensure the water doesn't escape so it can soak in deep around the damaged roots encouraging them to grow new ones. As long as you have a good root ball around your tree with soil not disturbed much it should take off. A tree with very few roots will have a 50-50 chance of surviving, especially when it is hot.