Wetsuit thickness guide: What thickness wetsuit do you need?

Wetsuit thickness & temperature guide

A wetsuit’s thickness determines its ability to keep you warm. Here’s a breakdown what thickness of wetsuit you’ll need for different water temperatures, and what other factors you ought to consider.

Temperature management is one of the keys to a prosperous surfing existence. In Europe at any rate, for most of the year, that means wearing a wetsuit of some description. Wearing the right type (or length) of wetsuit is important, but the key to striking the optimal balance between warmth, comfort, and performance is wetsuit thickness.

Being cold’s not much fun, and it won’t help your surfing either, but being too warm can cause equal discomfort. And when it comes to choosing a wetsuit, warmth isn’t the sole consideration. Wetsuits are made from rubber, usually a synthetic rubber called neoprene. The thicker the neoprene, the warmer the wearer. There’s a catch, though. Thicker neoprene is also less stretchy, so what you gain in warmth, you lose in mobility.

Understanding wetsuit thickness

Wetsuits range from just 1mm thick up to a toasty 6mm. Most are made from two different thicknesses of rubber, though thinner wetsuits are often the same thickness throughout. Thicker winter wetsuits occasionally comprise three different thicknesses.

Wetsuit thickness is measured in millimetres, and traditionally expressed with the different values listed in descending order, separated by forward slashes. A 3/2mm wetsuit (or 3/2) would be 3mm in the thicker panels and 2mm in the thinner panels. Typically this would involve 3mm neoprene around the torso and thighs, 2 mm neoprene for the shoulder, arm, and lower-leg panels. Often only the highest number is mentioned, so this same wetsuit might be referred to as simply a 3mm suit, even though parts of it are thinner than that.

Wetsuit temperature guide

The thickness of wetsuit you need depends mainly on water temperature. But clearly there are other factors involved, not least your own personal tolerance for the cold. There’s also air temperature to think about, along with wind, length of session, consistency of swell (long lulls = lots of sitting around), how old your wetsuit is, what other technical features it’s equipped with, and what wetsuit accessories (boots, gloves, etc.) you’re wearing with it. A brand-new, top-of-the-range, thermal-lined 3/2 with fully sealed seams is a very different proposition to an entry-level 3/2 that’s seen better days.

Water temperature Wetsuit thicknessWetsuit typeBoots / gloves / hood

24°C +
No wetsuit required!Just swimwear, maybe a jacket at most.

20 – 23°C
1mmShort sleeve / shorty etc. / wetsuit jacket with swimwear

17 – 21°C
2mmFullsuit / short sleeve / shorty etc.

14 – 18°C

10 – 15°C
4mmFullsuitMaybe boots

6 – 12°C
5mmFullsuitDefinitely boots, maybe gloves and/or hood

8°C and below
6mmFullsuitAll of them!

The above table is a ballpark guide indicating the appropriate wetsuit thickness for different water temperatures. It won’t be quite right for everyone – many a surfer has worn a 4/3 in 9°C water, or a 3/2 in 19°C water, and lived to tell the tale. But it gives you a rough idea. For the sake of simplicity, the figure in the thickness column refers to the thickest panel. A 4/3 counts as a 4mm wetsuit, a 5/4 or 5/4/3 as a 5mm suit, etc.

Also included in the table is the relevant type of wetsuit, along with whether you may need wetsuit boots, gloves, and/or hood. Personal tolerance and preference varies greatly with regard to the head and the extremities. Boots are almost always first, and are usually required around 12°C or 13°C. Most surfers probably resort to a hood before they do gloves, though it’s a close-run thing. Whatever the order, these tend to come out as the water drops from 11°C down to 8°C.

What thickness of wetsuit do you need for Cornwall?

Let’s take Cornwall, the UK’s surfing hub, as an example. Water temps average around 17 degrees celsius during the summer months, so a 3/2 fullsuit will keep you nice and snug. However the outgoing summer’s various heatwaves had the water hovering just shy of 20 degrees. Shorties and even swimwear were common sights in the line-up.

Our pal Paul in a 3/2mm Billabong wetsuit, the perfect thickness for a September morning on the north coast of Cornwall (water temp roughly 16 °C). Photo: Megan Hemsworth

For spring and autumn, a 4/3 should suffice, although you may be able to get away with a 3/2 well into November. In the depths of winter, however, temperatures will plunge into single figures, typically bottoming out around 9 degrees. Most surfers will be wearing 5mm wetsuits, all will be wearing boots; some manage to get by without gloves or a hood. A good 4mm wetsuit may also do the job.

What thickness of wetsuit do you need for the UK?

Again, it depends what time of year, and exactly where in the UK, and how much you feel the cold. On most coasts, you’ll need a 5mm wetsuit during winter, possibly something even thicker. Devon’s usually a degree or so colder than Cornwall in winter, Wales a degree or so colder again. It gets colder still in Scotland and Ireland. On the east coast of the UK, meanwhile, the relatively shallow North Sea takes less time to cool down and warm up. It’s colder than the Atlantic in winter but warmer in the summer.

xcel surfer reubyn ash barrelled on a trip to scotland
On a Surfdome trip to the Highlands with the Xcel Wetsuits crew last December, the water was about 8 or 9 °C. Reubyn Ash’s 4.5mm Comp X was up to the task, provided it wasn’t too windy – which allowed him faster reaction times for superior tube mastery. Photo: Sam Breeze

Currents can cause sea temperatures to rise or fall unexpectedly, independently of air temperature. Some years are significantly colder than others. Websites like magicseaweed, which also provides detailed surf forecasts for popular surf breaks all over the world, can tell you the current water temperature at a given beach.

The main thing you need to do is work out the temperature of the water you’ll be spending most of your time in. Then pick the right thickness of wetsuit, and you’ll be able to spend hours in the ocean nice and toasty. Clearly if you intend to surf year-round, the water temperature will fluctuate. Plan accordingly. You can probably just about survive on two wetsuits (a 5/4 and a 3/2 say), depending on the temperature range on your coastline. However you’re likely to be slightly too cold or slightly too hot for a decent chunk of the year.

Summer wetsuit vs. winter wetsuit thickness

As a rule of thumb, when people in the UK and Europe talk about summer wetsuits, they mean wetsuits that are 3mm thick or less, regardless of length. In other words, the kind of wetsuit that’s appropriate for a European summer. Wetsuits that are 4mm thick or thicker typically fall into the winter wetsuit category.

When people or brands talk about springsuits, they usually mean wetsuits that are short-sleeved and/or short-legged. This confuses things somewhat. The “spring” part of that formulation originally referred to the Australian spring, which is warmer than our summer. In fact you can take your summer wetsuit to Australia in the middle of their winter and you’ll probably be fine. It’s all topsy-turvy over there.

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