Cold, windy and clear sky days are by far the best for me.
Clear and calm is tough. It depends on the weather I had in recent days. If fresh birds were pushed down in the last couple days, then you could end up with a lot of "dumb" birds looking for food while they wait on the next weather front to continue the migration. If not, Then you could easily have a day that you see "high-flyers" and you get skunked.
Overcast usually isn't that great when the wind is calm, especially if you have snow or rain. The water is flat and the birds just stay hunkered down.
Overcast and windy can be good. Again, birds are looking for a safe place to get out of the weather or to feed.
The amount of wind is the key for me. If that water is moving, then the ducks tend not to sit for very long. It's hard for them to find a nice calm area to feed and rest. That means they are up in the air and looking..... hopefully they find my Benelli