You can dive dry year round, I wear mine pretty much year round. However, it may a bit of an overkill in the dead of summer. :coolingoff: I'll be the first to admit, I'm a real wus when it comes to the cold. I do have a 3mm wetsuit, but use it primarily just in the pool. I dive a Trilam (shell) drysuit & the amount of insulation depends on what I wear under it. I have, several undergarments of varying thicknesses. I've worn anything between just shorts & a T-shirt underneath (not recommended since the suit squeeze can pinch bare skin a bit) to light undergarments for warmer waters, to an undergarment that is the thickness of a winter coat for colder waters. Around this region, the water temperatures stay in the lower 40's below 60 ft of depth, so even if you don't dive year round, if you plan to do any deep diving, you have to plan your thermal protection to the temperature of the depth you're going to dive. Like I mentioned earlier, it is also wise to get some instruction either form a course or someone who has a fair amount of experience diving in drysuits, since with a drysuit (they are inflatable & have an exhaust valve) you are dealing with another air space like your BC. Its not difficult to learn to manage, it, but does take a little instruction. Also be aware that a drysuit in general costs about 5X's more than a wetsuit, but to me is worth it for the comfort & for the way it can extend the length of a dive. At depth, the quarry I dive is 42 degrees year round below 60 ft. In a 2 pc 7 mm wetsuit, I was only able to stay down for about 20 min. before getting too cold. With a drysuit it is nearly double that time. Each person is an individual, & the cold affect each person differently.