I think it also depends on your ability to provide winter care. Do you have a place where you can keep the tree above freezing, but in the 30s? or is it going to be largely unprotected and have it's pot buried in the soil. It is definitely not ideal for most. Leo excluded, because Leo, going to Northwestern for those four years really made me realize how much different temps can be right on Chicago's northern lakeshore. I can totally see that spring could be a problem for repotting on the lake. What I would say is, if you can provide adequate shelter from freezing winds, and keep the tree in an area that is above freezing, then you might have success. But, at the same time, you have to think of the fact that, really you only have two more months before winter, and 6 or so until you could definitively repot at a better time. Why not just wait?
If you are talking about repotting a weak tree because you aren't getting water and air percolation or you think there is a root related issue, then you would definitely need really good winter protection. But, if it's life or death, rolling the dice might be the right call. If you can wait, wait.