In PA, I think you'll need some sort of insulation. 600-800 would probably work. If you sit in a blind or on stand most of the day, boot covers or blankets can help extend the life of lower insulated boots considerably. They work very well if you drop a heat pack in each one in late Nov and Dec. I have sat 8 hours or so without feeling a twinge of cold this way and my feet almost always get cold when just wearing the highest insulated boots.