I just answered a PM from a Friend about winter water hunting and I thought this is worth sharing.
Oversized 5-7Mil neoprene waders allow you to don layers of wicking thermals to stay warm and dry.
Add thermal booties and wicking socks inside the wader's boots to keep Yer toes toasty and good rubber gauntlets to keep your hands warm (I like the Polar Paws) and you can brave some pretty cold water/air temps.
Hunting in the cold requires that you stay alert to conditions at all times as there is no room for mistakes!
When temps dip into the mid 30s, no wind, water perfectly calm, sun is shining I'm at the lower limit for hunting no matter how well insulated I am!
Once you start digging you'll usually warm up enough to be comfortable for at least a short hunt, but you have to constantly be aware of your physical condition and what your fingers and toes are telling you!
Condensation will build up in the gloves and after a while they will start to let your fingers get cold!
Exertion of digging will cause the waders to start to get damp inside too allowing the cold to enter!
Use common sense, be alert, avoid extremes, and you'll do alright.
GL&HH Friends and Fellow Hunters,
CJ