We have freezing weather here starting last week. I'm planting beds today and tomorrow. I normally like to get my stuff in the woods done in late August and the beds here at the house just after that. Just too much to do this year. The transplants are in the mud room thawing out (they are frozen into a block with peat) and I'll put them in tomorrow.
I think everything will be ok, but still, its much nicer to have them in the ground while you still have nice weather and don't feel rushed by bad weather.
Since you are farther south than I am, I'm sure you will be just fine. I wouldn't advise you wait too long though.