i dive year round north of puget sound (Georgia Strait and Discovery Passage and north) in a wet suit in complete comfort. I don't understand at all so many people claim you need a dry suit, i think this is a misconception the manufacters are only too happy to see continue. I have several dry suits ( i dive regularly for fishfarms where you are required to wear a specific dry - neoprene for westcoast pacific and latex/urethane for inside strait) but the fact is diving in a wet or semi wet is so much more comfortable and streamlined...you can swim in a wet suit... The only time i feel cold is when i get out of the water and all that warm water pours out of the bottom of the suit...it feels like a massive horse piss and is just as satisfying except you will feel a little cold untill you do some moving around to replace the lost heat. For the slight inconvenience of a small cold period at the beginning of the dive, in return you get increased mobility, streamling, use less air and swim with greater ease...and you are in contact and balance with the enviroment in a way you are not with a drysuit. I want salt water on my skin when i dive...it's part of the reason i love diving...also i l dive cuz it's another type of swimming...swimming sucks in a drysuit.
My personal experience is you feel a little cold jumping in...you move around and in less than a few minutes i feel perfectly warm for the entire dive...(let me emphasize: absolutely comfortable and happy) i'm in fact much more comfortable for swimming (as opposed to just sinking, paddling around a little and than ascending) than in a dry suit. And i have neoprene and urethane drysuits i could use, but i like to swim...not sink, drift and rise.
Obviously you use less air in a wet, you move faster and easier and your streamlined...and as to the issue of cold, in the Pacific northwest: you get a good 7mm 'tight fit' wet or semi wet and your good to go fall/winter/spring. I think a 7mm is too much for summer diving.
Some people will take offense at this but there is almost a psychological fear of cold and unatural expectation of comfort that it has held people back from the fact that todays 7mm wet suits are perfectly suitable for Pacific NW year round diving. With a good snug wet suit you will face a bit of cold for a few minutes...(welcome to the Pacific NorthWest) but the fact is once you warm the inner layer of insulating water, it does not pour out (this of course requires a good snug fit, full hood with bib tucked under and good long gloves)...not from pressure (it's water not air) and as a result of the easier, freer movement...you do move more and yet use less air for the amount of dive you get and this makes it a far more enjoyable way to dive. In fact i think that no healthy person who can swim needs a drysuit in the Pacific NorthWest unless you are a commercial diver who does very little swimming.
In fact they work so well one improvement the companies could make is a semi sealed wetsuit (sealed to air, not water) so that the water in the suit can be held in there until the diver feels like releasing it.
I think most divers don't realize how effective water is at keeping you warm (much more effective than air) and that todays wetsuit does hold in the water effectively (provided it's snug and tight at the arm, neck and leg hems). This year in January i've done a few 45 metre dives in a sherwood 7mm two piece on the navy wreck at Quadra Island (Campbell River/Canada)...hey i was perfectly warm! Not a little warm either...perfectly absolutely warm and hey, i was in the water...which is whtat it's about! All the other divers were wearing drys except me and the guides (most of the divers were Americans) and they thought we must be super cold water adapted canucks...well we are not. We are just not afraid of a little cold...and the fact is we had more of a healthy vigorous dive, we swim underwater with a ease that you cannot with a dry suit, and i was never once cold underwater...in fact underwater i am perfectly warm... So i recommend a cold water wet suit over a dry suit empatically.
