Views: 0 Author: Site Editor Publish Time: 2025-10-24 Origin: Site
The numbers 5/3, 4/3, 3/2, etc. refer to the thickness of the neoprene in millimeters and therefore describe the warmth of the wetsuit. 5/3 wetsuits are 5 mm thick in the torso and 3 mm thick in the arms and legs. The same logic applies to 4/3 and 3/2 wetsuits that use thinner rubber and therefore do not retain warmth as well.
Your choice will depend on the season you plan to use the suit, the water temperature, the wind speed, and how cold you personally are. In 13 degree water, as you would find in the winter off the Atlantic coast of France, you would choose a 4/3. Once the water temperature reaches 16 degrees in the spring, you can switch very comfortably to a 3/2. For the winter throughout most of the UK, you will need a 5/3.
The thickness of your wetsuit you need depends on the temperature of the surrounding water. Of course, there are no hard and fast rules, and if you are particularly susceptible to cold water (like I am!) . Remember, the best suit is the one you feel most comfortable in!
As a general rule, some guidelines on how much thermal protection you need are
85°F / 30°C and above - Sunsuit and surfboard for sun and scuff protection. If you are particularly susceptible to cold (like me), you can wear a 1 mm short sleeve undershirt to keep your core warm. You'll be boiling in a full suit!
80-85°F / 27-29°C - 3 mm shorts or 2/3 mm full suit
73-79°F / 23-26°C - 3mm to 5mm full suit
66-72°F / 19-22°C - 5mm to 7mm full set
50-65°F / 10-18°C - 7mm, 9mm, Semi-Dry or Full Dry
50°F / 10°C and below - Drysuit
❗️Please note that there are no hard and fast rules. Each person is different, depending on cold tolerance, habits, body temperature and the physiological makeup of the body. Fat is an excellent insulator!