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Everything You Need to Know About Wetsuit Thickness

   October 9th, 2018   Posted In: Articles  

Everything You Need to Know About Wetsuit Thickness

If you’re new to wetsuit shopping, how do you know what thickness to buy? Here’s your ultimate guide to wetsuit thickness and how to choose yours.

The wetsuit market is predicted to reach $1.18 billion in the next four years. But before you join that market and buy your first wetsuit, you should understand what you’re getting. Not all wetsuits are created equal. Different thicknesses can protect you from different water temperatures. One wetsuit simply won’t work for every body of water out there. That’s why we’ve put together this wetsuit thickness guide for you. Keep reading to learn everything you need to know about choosing the best wetsuit for your needs.

How Does a Wetsuit Work?

A wetsuit isn’t supposed to keep you dry. It’s supposed to keep you warm. Wetsuits are made of neoprene. This neoprene is full of tiny cells filled with air. In other words, your wetsuit is covered in small air bubbles. This turns it into a form of insulation.

But water conducts heat 25-40 times faster than air. So the neoprene traps a thin layer of water inside the suit against your skin. Your body heats up this layer of water and keeps your body from losing too much warmth. Thicker wetsuits provide more insulation than thinner wetsuits. That’s what makes choosing wetsuit thickness so important.

How to Choose a Wetsuit Thickness

Before you can find a wetsuit that’s the right thickness for your needs, you have to understand three different wetsuit measurements. For example, you might find a wetsuit with a measurement that looks like this: 4/3/2. These numbers each represent a part of your wetsuit. The first number measures the torso area of your wetsuit. The “4” means the torso is 4mm thick. The second number refers to the legs. In this case, the legs of the wetsuit are 3mm thick. The last number represents the arms. This wetsuit has arms that are 2mm thick.

Sometimes wetsuit measurements only have two numbers. So the measurement might look like this: 4/3. This could mean two different things. Sometimes the arms and legs of the wetsuit have the same thickness. Other wetsuits might have two numbers because the suit itself doesn’t have any arm sleeves. Every wetsuit is always measured in millimeters.

Why Does a Wetsuit Have Different Thicknesses?

The torso of your wetsuit must be thicker than the rest of the suit to ensure your body’s core temp doesn’t drop too low. If your core heat drops, you’re at risk of suffering from hypothermia. Because it’s so thick, the torso neoprene isn’t very flexible. The legs and arms of your wetsuit are thinner so you can bend and move them.

Your Wetsuit Thickness Guide

The temperature of the water you surf in will dictate the wetsuit thickness you need. This can change depending on seasons, swells, and region. Don’t ignore the temperature of the water.

Trying to surf in cold water with a thin wetsuit is dangerous. Cold water puts you at risk of cold shock, physical incapacitation, hypothermia, and circum rescue collapse. If your hands, feet, and ears start to go numb, you may need to wear gloves, boots, and hoods as well.

So what thicknesses work for what temperatures? Here’s a quick guide:

  • 2mm – This is about as thin as a wetsuit can get. It’s suitable for warm waters that are 65 degrees Fahrenheit or higher. You won’t want to wear thicker wetsuits in water this warm because they can cause you to overheat.
  • 3mm – A 3mm wetsuit provides enough protection for waters between 65 degrees and 54 degrees Fahrenheit. Depending on your region, you can wear this wetsuit during the summer and during the winter.
  • 4mm – You can wear a 4mm wetsuit in waters that get as cold as 50 degrees Fahrenheit. At this temperature, you might also want to add wetsuit gloves or boots.
  • 5mm – Your 5mm wetsuit can withstand 46 degrees Fahrenheit waters. If you go surfing during the middle of winter, you’ll need a wetsuit with this level of thickness. This temperature requires gloves and boots, and you might want to put on a hood as well.
  • 6mm/7mm – These two thicknesses offer the most protection, and you can wear them in waters that get as cold as 32 degrees Fahrenheit. You must wear gloves, boots, and a hood in this water.

Different Wetsuit Seam Seals

Another part of the wetsuit you have to consider is the wetsuit seam. The seams of your wetsuit play into the overall insulation ability. Wetsuits with a thickness of 6mm will have more heavy-duty seems than a wetsuit with a thickness of 3mm. Here’s a quick breakdown of the three different types of wetsuit seams:

  • Flatlock Stitching – This type of seam lets the most water into your wetsuit. Though stitched, the seams feel natural and comfortable against your skin. You’ll find flatlock stitching on wetsuits with a thickness of 2mm and below. Some 3mm wetsuits might have this kind of seam as well. That means you should only wear a wetsuit with flatlock stitching in waters above 62 degrees Fahrenheit.
  • Sealed – This type of seal uses a method called blindstitching. Instead of going all the way through the neoprene, the stitching goes in and out the same side. Before blindstitching, manufacturers also glue the wetsuit panels together. This makes the seam watertight. Wetsuits with 3mm and 4 mm thicknesses can have this type of seam. Don’t wear these wetsuits in waters colder than 55 degrees Fahrenheit.
  • Sealed and Taped – Not only does this seam have glue and blindstitching, but it also includes tape. The tape goes on the inside of the seam to add durability. It also prevents any water from entering and escaping the suit. This type of seam is heavy duty. It can protect you in waters with temperatures under 55 degrees Fahrenheit. You can find this seam on wetsuits with a thickness of 4mm through 7mm.

Picking the Right Wetsuit Thickness

Choosing the right wetsuit thickness will protect you from cold water temperatures. And the next step after buying a wetsuit is making sure you have a good rashguard. This will prevent the wetsuit from rubbing against your skin and forming rashes. At the same time, it also gives you another layer of insulation.

Not sure if you really need one? You should read up on why it’s important to always wear a rashguard under your suit.

Can’t Find The Right Size? Go Custom

Now you know why choosing the right wetsuit thickness is important. But you also need to make sure it’s high-quality and fits properly. That’s where we come in. At the Wetsuit Warehouse, we have wetsuits for surfing, SCUBA diving, paddling, and general use. We also have a wide selection for men, women, and kids. If you don’t find the right size, we’ll customize it! If you need help finding what you’re looking for, give us a shout. We’ll be happy to help.

Chris "Mole" Moleskie is the Founder, President, and CEO of Wetsuit Wearhouse. Mole grew up in the water on the East Coast. After graduating from Salisbury University, on Maryland's Eastern Shore, he headed to San Diego to find the eternal Ocean City. Wetsuit Wearhouse was formed a few years later in 2001. He swims, surfs when he can, SCUBA dives, wakeboards, SUPs, snowboards 15-20 days a season, and recently fell in lust with wakesurfing. Mole spends his summers at the not so secret Wetsuit Wearehouse Testing Facility on the Potomac River.

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