I don't know if I can add too much to this as I don't have hardly any experience. I have only been diving once so far (I am not counting the pool), the first of the two Open water dives for my certificate. Last Tuesday afternoon on 4/25/06, Air temperature was in the upper fifties, lower sixties and I don't know the water temperature. This was in a small local quarry not far from Jefferson City owned by the dive shop. On hand where the instructor, three other experienced divers to assist the Instructor and four of us students.
Now I am normally the first person in the room to get cold, I can't stress this enough, I like my house to be about 70-72 degrees, but I was warm all through the dive and even after the dive while standing around and yapping. Mostly listening to the three experienced divers complaining about the cold. Two of us students where just fine and very comfortable the other two I did spot shivering after the dive. The instructor was wearing a dry suit so not surprisingly no complaints where herd from him.
I will admit that the first leak of water around the wrists and ankles and leaking through the zipper in my wetsuit where like ice water but by the time I had walked in enough to float and put on my fins it was not cold. I guess the whole theory of the body temp warming up the little bit of water that leaks in the wetsuit plays out fairly well. I was wearing a 7mm Aqualung "Aqua Flex" full suit with a 6mm hooded vest over that. Their was a bit of a cold shock on the cheeks and lips at the first thermocline around twenty foot and then again at the second down at about 40 foot. The first time through this was a bit of a shocking cold but quickly subsided and passing through the thermocline again did not have the same result. I made sure a couple of times to reach up and feel my cheek and lips to see if they where just numb and that did not seam to be the case.
Me and my dive partner (Charley, the other male student) completed all of the tasks quickly with the instructor and one of the experienced divers while the other two experienced divers tended to the other two students. Two ladies whom where having more difficulties than Charley or I getting organized with their equipment. They all then began to work with the two ladies while me and charley simply played around on our own for nearly an hour. We went down and up several times and where having a lot of fun despite the fact that neither of us where coming any ware near mastering buoyancy control. Finally we came up and saw that everyone was working on getting out of the water. The instructor basically told us that everyone else was to cold and where done for the day. I looked at Charley and he looked at me and I know we where sharing the same thought, which we talked about later. Not only where neither of us cold we both felt quite warm!
I suppose that I could have been having so much fun that I had not noticed that I was cold but if that where the case I would have expected the start getting cold some time after the dive. Their must have been twenty to thirty minuets at the dive site of standing around in my swim trunks and a polo shirt after removing my wetsuit. As dusk set in we headed out, unfortunately after leaving the quarry Charley had to stop at the corner gas station due to his truck being stuck in 4WD. That was another hour standing around waiting for someone to come and get the truck in my swim trunks. This was now after sunset and it had just started to rain as I started to feel somewhat cold.
I suppose this is, like so many things, a very personal issue. I am sure that depth and time also have their part to play in this issue. I took the class room and pool part of this course in mid March, had to wait until April for the open water dive due to concerns about the cold. And though we where scheduled to take the second open water dive (getting me my certificate) the very next afternoon on 4/26/06. the plan now, due to the cold is to continue this on May the third, after talking to the instructor today he mentioned "the longer we wait the warmer it will get" indicating their may be some encouragement to put it off again. With all of the talk and knowing my nature I was expecting to have a horrible time with the cold, but I was quite warm.
To be honest I am not sure how to respond to the question "When is the water warm enough?" which means I suppose I have nothing to add to this thread. hua, bummer...