The thickness of the wetsuit you need will vary depending on the water temperature range that you will be using it in and the activity you intend to do. You will also need to consider the air temperature, wind speed, activity level, and how sensitive you are to getting cold to purchase the right wetsuit for you.
Wetsuit thickness ranges from 0.5mm to 6/5mm, meaning there is one to suit every need. In warmer water temperatures, you should opt for a thinner wetsuit, and in colder climates, you will want a thicker wetsuit to protect your body from colder water and air.
The thickest wetsuits are best for 42 degrees Fahrenheit and under, with the thinner wetsuits better for temperatures ranging from 62 degrees to 75 degrees Fahrenheit.
Consider the temperature and the other factors mentioned when deciding how thick a wetsuit to purchase. If you do feel the cold more, we recommend upping the thickness slightly to keep yourself warm at all times.