Shawn, welcome to Pond Boss.
Ideal situations are to be able to work the pond basin when it is free of standing water. I could see some scheduling benefits for the pond builder to do the excavation during the winter, but my guess would be that the finish work would need to be done in warmer temperatures. If the hole was dug in the winter, I would think you would start to accumulate some water before the finish work.
I have no expertise on this, however, so let's see what others have to say.
