In order to swim comfortably in the bracing waters of Lake Michigan, I gear up in layers.
1) Tyr jammer swimsuit
2) ONeill 13 Ounce Thermo-X Short Sleeve Crew designed to keep my “core” warm
3) A full body wetsuit
The final cold water accessories are a neoprene swim cap, neoprene booties, and neoprene diving gloves.
This is the gear set up I use for swimming in 50F – 56F (10C – 13.3C) water. The only other items I add to this are my swim goggles as well as petroleum jelly to use on the exposed areas of my neck and face.
Once the water temperature exceeds 56F (13.3C), I “pare down” my equipment accordingly:
57F – 62F (13.9C – 16.6C) – Eliminate the gloves, booties, and neoprene cap (use latex swim cap)
63F – 68F (17.2C – 20.0C) – Eliminate the thermo shirt and consider switching to a “farmer john” or “shortie” wetsuit
69F+ (20.5C+) – Eliminate the wetsuit
Let me emphasize that these are guidelines that I formulated based upon my personal experience with cold water swimming. Other people might have different temperature thresholds, and they might very well be comfortable swimming without a wetsuit at much lower temperatures. Indeed, there are multiple factors that influence one’s cold water tolerance such as age, gender, body fat%, and overall physical conditioning. However, this is a good benchmark if you’re just starting out. You can always adjust upwards or downwards once you get more exposure to varying water situations.