So, wetsuits, drysuits, etc. I paddle year round, and have taught cold water paddling workshops for our club. The biggest message we try to get across is that you need to swim your gear to know how well it will work. Find a nice safe place you can wade in and submerge and still stand up. Put on what you plan to paddle in. Walk in, dunk, and stand there, up to your neck, hands in the water, for the amount of time you think it will take you to rescue yourself or get rescued. Still ok at the end of that? Warm enough to still have hand/finger coordination snough to grip your paddle, undo knots, etc? if so, your gear may be good enough for that water temperature.
Not only do you need a wetsuit or drysuit, but you need foot, head, and hand insulation too.
For shoulder season here in the Maryland bay area (water temps of about 55-65 degrees F), I will wear a farmer john wetsuit with thick polypro or kayaks specific thermal shirt and a paddling jacket, and neoprene boots of some sort. By the time the water temp drops enough for me to need gloves (below 55) I am in a drysuit, under which I am wearing 200-300 level fleece top and tobbom, and warm socks, and a neprene skull cap that covers my ears, along with neoprene gloves.
Your experiences may vary, but the big lesson is to practice swim your gear in the water temps you will be paddling, for the amount of time it will take to rescue yourself or be rescued.