Diving dry is a much different experience from diving a wetsuit. I’m sure we can have a lively debate on which is better. I don’t have an opinion there. For me, it’s all about dressing for the weather.
I now have quite a few dives in my suit with water temperatures ranging from almost 60 degrees down to 39 degrees. The biggest realization for me as a new drysuit diver is that dry does not equal warm. Dry equals dry.
It is the air within the suit that traps and retains heat and provides insulation. It is the insulation layers under the waterproof shell that trap air and let my body warm it. In fact, without air, the 7mm 2-piece wetsuit Cam dives is warmer since the material has better insulating properties. My drysuit itself has no significant insulative properties. I wouldn’t want to go back. I was never comfortable with a 2-piece 7mm suit. There is no doubt that air is a great insulator. Warming that layer of water between a wetsuit and the body can take significant energy and provides fewer insulative benefits. There is also a constant flow of cold water through the wetsuit. But that does not mean that every dive is toasty warm for me. Nor does that mean that every dive is miserable cold for Cam.
For me, it is a fine balance between keeping enough air in the suit to be comfortable, and having so much that it makes buoyancy hard to control. I’m still learning there. The big difference I see with diving dry is just that. I come out of the water dry, protected by a layer of air. Thus, I am not further chilled by evaporative cooling. Cam and I agreed after a dive in 45 degree quarry water that we were both chilly, but could have gone longer. A drysuit is a great tool to have in the toolbox and I don’t want to go back. However, it is not the panacea of warmth in the Midwestern winter that I and many others I have talked to believed it is. It does makes it easier to dive longer and be more comfortable. It’s Just not wet.