Is a 3MM Wetsuit Ok for Winter?

Is a 3MM Wetsuit Ok for Winter?

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Picking the right wetsuit thickness can be overwhelming. A thin wetsuit will make you quiver, while a thick one can be restrictive. Not to mention, you’ll end up sweating a lot during the hot weather. For that reason, many people might prefer thin wetsuits with a thickness of 3 mm.

However, with winter temperatures often dropping below 70ºF, figuring out whether or not a 3 mm wetsuit is warm enough can be tricky.

So, is a 3mm wetsuit ok for winter? That’s what we’ll discuss in this article. So, keep reading to find out!

Read my wetsuit thickness guide.

Is a 3MM Wetsuit Ok for Winter?

Generally, no, a 3 mm wetsuit isn’t suitable for winter conditions. Water temperature is the most crucial factor when it comes to wetsuit thickness. The colder the water is, the thicker your wetsuit needs to be.

A 3mm wetsuit is typically considered suitable for warmer water temperatures, between 62ºF and 68ºF. Such temperatures are found in the summer or tropical areas.

However, you can still use your 3 mm during the winter in warm regions where the water temperature doesn’t get cold. That’s especially true for the tropics. Those areas don’t experience seasonal changes and remain hot throughout the year!

That said, people differ in their ability to tolerate the cold. For some, going for a morning swim in freezing water is as easy as pie. So, wearing a thin 3 mm wetsuit might keep them warm during winter.

Why Do Some People Tolerate Cold Water Better?

As you might have guessed, genetics plays a role in cold tolerance. You see, the human body contains two types of muscle fibers: fast-twitch and slow-twitch.

During exercise, fast-twitch muscles anaerobically and contract quickly. Those muscles are handy for explosive movement exercises, such as weightlifting and sprinting. They also help keep us warm.

Generally, humans respond to chilly weather by shivering. The former motion happens due to fast-twitch muscles’ quick, repeating contractions. Why do we quiver? Well, that’s because that speedy movement releases heat energy, keeping you warm.

However, all those functions are only possible in the presence of a particular gene that codes for actinin protein. The problem is that fast-twitch muscles fatigue easily. So, the generated heat is only temporary.

Slow-twitch muscles, on the other hand, respire aerobically and are partially contracting. As a result, they’re constantly producing heat energy.

Because those muscles are always in motion, they don’t fatigue like fast-twitch muscles. Additionally, the former muscle group doesn’t code for actinin protein. That means slow-twitch fibers keep us warm long-term without the shivering motion.

Consequently, you might not need a thicker wetsuit during the winter if you have a higher slow-twitch muscle percentage.

Still, it’s best to always check the local weather conditions and water temperature before scuba diving to ensure your safety.

Why Does Wetsuit Thickness Matter?

Wetsuit Temperature Chart

Before we get into the best wetsuit thicknesses for winter, let’s understand how wetsuits work.

You’ve probably heard that wetsuits keep us warm by trapping water. As you might know, heat transfers from high-temperature objects to colder ones. Since our bodies are usually hotter than the ocean, they warm the trapped water.

That heated layer keeps you warm during your water sports adventure. However, that’s not the only benefit of the diving outfit. Most wetsuits are made of neoprene, a synthetic rubber. Not only does it trap water, but neoprene is also an insulator, all thanks to its foam-like structure.

This synthetic rubber contains tiny chambers that trap nitrogen. Why is that important? Well, because most gases are poor heat conductors. So, they act as insulators, preventing the cold ocean from cooling the warm water layer beneath the suit.

As you can tell, thicker neoprene panels mean more gas chambers and better insolation. Consequently, the thick suit traps body heat efficiently, keeping you warm in freezing water.

However, wetsuits are only effective with proper fitting. If your suit is too loose, ocean water will seep into it, lowering your body’s temperature.

What Thickness Wetsuit Do You Need for Winter?

Now for the important bit: which wetsuit thickness do you need for winter?

Generally, wetsuit thicknesses can range from as little as 2 mm to 7 mm. Of course, thin suits of 2, 3, and 4 mm thickness are suitable for summer. You can also wear the latter in the fall or early winter.

4.5-5 mm suits are more of a one-size-fits-all option. They’re layered enough to keep you warm during the winter when the water temperature drops to 52ºF. Yet, they’re not too thick to impair your movement. So, they make for great wetsuits throughout the year.

However, if the temperature drops below 50ºF, you’ll likely need to upgrade to thicker wetsuits.

Additionally, you’ll need to wear other accessories, like hoods, gloves, and boots, with 5 mm suits or thicker. That’s to ensure you keep areas susceptible to cold, such as your extremities, warm.

How to Tell Wetsuit Thickness

From the above, you can see that most brands express wetsuit thickness in millimeters (mm). That’s the easy part to figure out. However, you might come across wetsuit thicknesses written in two numbers, such as 3/2. So, what does that mean?

The first number typically represents neoprene’s thickness in the torso area. As for the other number, it indicates the arms’ and legs’ thicknesses. In the case of three numbers, the second refers to neoprene thickness in the legs, while the last number represents the arms.

As you might have noticed, the rubber panels in the torso are thicker than in the extremities, all for good reasons. For one, it helps maintain a warm core, which is crucial to prevent hypothermia.

Plus, thicker neoprene is less flexible. For that reason, it’s suitable for the torso because you don’t move that area much while diving.

Conversely, the thinner the synthetic rubber is, the less restrictive it is. That makes it ideal for the arms and legs since that’s where your body is in constant motion.


So, is a 3 mm wetsuit ok for winter?

The short answer is no. A 3 mm wetsuit is suitable for the summer when the water temperature doesn’t drop below 62ºF.

However, you can wear the former thickness in the tropics throughout the year. That’s because the water in those regions doesn’t experience seasonal change.

For colder climates, you need to wear a thick wetsuit of 5 mm or above. Additionally, you should combine it with hoods, boots, and gloves to keep your extremities warm. That way, you ensure your body maintains a high temperature, allowing you to enjoy scuba diving during the cold months!

Jack Thompson

Jack Thompson, a scuba diving enthusiast from San Diego, has spent over a decade exploring the underwater world across the globe. Sharing his passion through captivating stories and informative articles, Jack aims to inspire others to embark on their own scuba diving adventures and uncover the ocean's hidden treasures. You can also follow him on Twitter.

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