Before I transferred to the east coast, water temps below 40 degrees were common year round at any depth below 100' and 35 to 39 degree water temps were the norm, except on ice dives where it would be 32-33 degrees right under the ice.
Fresh water begins to expand at 35 degrees, and begins to rise, so you see 32 at the under surface of the ice and 35 at the bottom. That's why bodies of water freeze at the surface rather than at the bottom, and we're fortunate that is the case as the ice insulates the rest of the water and prevents the entire body of water from freezing. If that were not the case, we'd be living (or not) on a giant ball of ice.
My preference was a good fitting 7mm neoprene dry suit. The insulating properties of the thick neoprene shell prevent the condensation you get inside a bi-lam or tri-lam thin shell suit. Plus, if it floods you still have a very effective semi-dry wet suit. On dives in the 40 degree range, a wicking base layer undergarment was sufficient, and in 32-35 degree water I'd add a fleece undergarment and ensure I ran the suit with enough gas to keep undergarment fully lofted.
Now, with most of my diving in 68-70 degree water - but up to 5 hour long dives, I dive a 4mm compressed (not crushed) neoprene drysuit with an wicking base layer under garment.
In both cases, the suits still swim very much like a wet suit, and in like a thin shell suit, they won't bite you if you run them significantly squeezed.
Fresh water begins to expand at 35 degrees, and begins to rise, so you see 32 at the under surface of the ice and 35 at the bottom. That's why bodies of water freeze at the surface rather than at the bottom, and we're fortunate that is the case as the ice insulates the rest of the water and prevents the entire body of water from freezing. If that were not the case, we'd be living (or not) on a giant ball of ice.
My preference was a good fitting 7mm neoprene dry suit. The insulating properties of the thick neoprene shell prevent the condensation you get inside a bi-lam or tri-lam thin shell suit. Plus, if it floods you still have a very effective semi-dry wet suit. On dives in the 40 degree range, a wicking base layer undergarment was sufficient, and in 32-35 degree water I'd add a fleece undergarment and ensure I ran the suit with enough gas to keep undergarment fully lofted.
Now, with most of my diving in 68-70 degree water - but up to 5 hour long dives, I dive a 4mm compressed (not crushed) neoprene drysuit with an wicking base layer under garment.
In both cases, the suits still swim very much like a wet suit, and in like a thin shell suit, they won't bite you if you run them significantly squeezed.
