I am still debating over whether to get a dry suit for cold water winter paddling (water temps in the low 50s and air temps about the same or maybe a bit colder.
Here is my question…at what air temperature will you start to overheat in a full dry suit?
It would seem to me that they would be pretty warm and that you might get pretty uncomfortable on 50 degree days.
Also, given the fact that the warm air temps might may you want to wear very little underneath for insulation (maybe a light base layer) would the suit still be enough to keep you warm in a submersion? You would of course be dry, but without much insulation underneath would the suit still do its job?
thanks
matt
56.75 degrees Farenheit
give or take. Depends on how hard your are working, how cold the water is. Just need to make sure you are drinking lots of water. One can always roll or jump in for a dip to cool off.
I’ve worn mine into the 70’s…
…and been comfortable. You adjust your inner layers and use the water to cool off as necessary. No problem.
Pretend you are poikilothermic, like a
lizard, and use the environment to adjust temperature. As suggested above, running cool water over your suit will help. If on a river or near shore, you can paddle in the shade where possible.
My winter experience in Atlanta is that my drytops can feel too warm over 60 degrees, if I am exercising fairly heavily. However, if the water is cold, then I will tolerate some feeling of being too hot in exchange for the safety factor which exists if I get pitched into that cold water. My past experience with a full wetsuit was that fighting all that neoprene during hard paddling would cost a lot of energy, and leave my hotter than if wearing a drysuit.
Someday manufacturers may find a way to allow us to exchange the air inside drysuits, both for cooling and to remove moisture which has not escaped through the “breathable” fabric.
Drysuits are tuneable
Like wool, they have a wide comfort range, though for differing reasons.
Caveat: what is comfortable for YOU is not necessarily what’s comfortable for me, and the comfort threshold varies even within one person on different days. I assume this is why tsunamichuck posted his answer 
Still, you have the option of using one or several thin or medium or thick underlayers. You have the option of burping the drysuit as empty of air as you possibly can (shrinkwrapped to your limbs) or of letting a small amount of insulating air remain inside (not too much, though!!!)
Bottom line is that nobody else can answer this question for you. Above 80 degrees in a drysuit is too hot for me but I still will wear it in such temps if the water temp is cold AND I am going to do a lot of rolling. (There is nothing like a drysuit to allow you to do many rolls for an hour or more.)
For winter paddling, getting too hot just is not a problem. Your location may be different, though.
What she said
Drysuits have the widest range of temperature comfort and safety for me.
At 50/50 temperatures I like a dry suit. I can wear mine with thin underlayers in air temps up to nearly 80. I think the question is, is there anything else better for your winter conditions?
Today I was a tad too warm with capaline longs 100 wt fleece and a dry suit. I took a dip of my friends bow and was fine. If I had been in wet-wear the dip wouldn’t have been nearly so pleasant. If I hadn’t had the fleece I think I would have been fine for a reentry but probably wouldn’t have wanted to spend hours in the 50-55 or so degree water. I wouldn’t have wanted to spend hours in the water in farmer john, hydroskin shirt, and paddling jacket, either. And that would have put me back to being too warm in the air.