Wetsuit Thickness Guide: Chart by Water Temperature 2027

What do the numbers on a wetsuit mean?

Wetsuits are labelled with two or three numbers, such as 3/2, 4/3 or 5/4/3. The first number is the thickest panel, usually the chest and back, where your core needs to stay warm. The second is for the arms and legs, where you need to move. A third number often marks even thinner panels on the arms or shoulders.

Why it works: neoprene is foamed rubber full of tiny gas bubbles. A thin layer of water between your skin and the suit is warmed by your body, and the neoprene insulates it from the cold sea. Thicker material insulates better but makes the suit stiffer, and you'll feel every extra millimetre in your shoulders when paddling.

Common styles:

Shorty: short arms and legs, usually 2 mm. For warm water.
Springsuit: short legs with long arms, or the other way round.
Full suit (steamer): full-length suit, the standard for Atlantic surfing.
Accessories: boots (booties), gloves and hood, usually 2–7 mm.

Wetsuit thickness chart by water temperature

This chart follows the guidance most commonly given by major surf retailers and brands (including evo). It assumes normal surfing activity. The ranges overlap on purpose, because wind, air temperature and how easily you feel the cold all play a part.

Water temperature	Wetsuit	Accessories
above approx. 22 °C	Boardshorts/bikini, rash vest or neoprene top	none
approx. 18–22 °C	2 mm shorty or springsuit, or a 2/2 full suit	none
approx. 16–20 °C	3/2 mm full suit	none
approx. 14–17 °C	3/2 to 4/3 mm full suit	boots if needed
approx. 11–14 °C	4/3 to 5/4 mm full suit	boots, possibly gloves and hood
approx. 6–11 °C	5/4 to 5/4/3 mm full suit	boots, gloves, hood
below approx. 6 °C	5/4/3 to 6/5 mm, often with built-in hood	5–7 mm boots, gloves, hood

In Fahrenheit, the key thresholds are roughly: 22 °C ≈ 72 °F, 17 °C ≈ 63 °F, 14 °C ≈ 57 °F, 11 °C ≈ 52 °F.

What pushes you thicker or thinner

Wind: strong or offshore wind chills you fast while you wait in the line-up. When it's windy, go thicker.
Air temperature and sun: with 30 °C air and sunshine, a 3/2 can be fine in 17 °C water. With fog and 18 °C air, you'll freeze in it.
Session length: surf lessons often last 2–3 hours. The longer you're in, the warmer your suit should be.
Your level: beginners spend lots of time standing in white water and getting soaked. Experienced surfers paddle more and generate heat, but also sit still longer.
Build: leaner people get cold faster. If you feel the cold easily, go one step thicker.

Atlantic water temperatures by month

The figures below are average sea-surface temperatures over roughly 10 years from seatemperature.info (checked in November 2026). Individual days can be noticeably warmer or colder. In Galicia, summer upwelling of cold deep water can drop the sea by one to three degrees for a few days at a time.

Month	Galicia (Louro/Muros)	Basque Country (Zarautz)	France (Biarritz)	Central Portugal (Peniche)	Southern Portugal (Sagres)
January	13.3 °C	12.9 °C	12.5 °C	14.6 °C	16.2 °C
February	12.9 °C	12.2 °C	12.0 °C	14.1 °C	15.4 °C
March	13.1 °C	12.5 °C	12.5 °C	14.2 °C	15.3 °C
April	14.0 °C	13.6 °C	13.9 °C	14.9 °C	16.0 °C
May	15.3 °C	15.9 °C	16.4 °C	15.9 °C	16.9 °C
June	16.5 °C	19.2 °C	19.7 °C	17.0 °C	18.1 °C
July	17.2 °C	21.8 °C	22.2 °C	17.5 °C	18.6 °C
August	17.3 °C	22.5 °C	22.7 °C	17.8 °C	19.0 °C
September	17.0 °C	21.1 °C	21.2 °C	18.1 °C	19.6 °C
October	16.3 °C	18.6 °C	18.6 °C	17.7 °C	19.6 °C
November	15.1 °C	16.0 °C	15.7 °C	16.6 °C	18.2 °C
December	13.9 °C	14.0 °C	13.7 °C	15.4 °C	17.1 °C

The key point: Galicia and Portugal's west coast rarely average more than 17–18 °C in summer, while the Bay of Biscay (Basque Country, south-west France) passes 22 °C in August. If you assume "Spain in July = warm water", you'll pack the wrong suit for Galicia. If you already surf in the UK, Ireland or the Netherlands in a 4/3, bring the same suit.

Illustration of a wetsuit thickness chart: a thermometer next to three wetsuits of different thickness with boots and a hood

What wetsuit do you need for Galicia?

For the Galicia surf season, which on Semesterkur trips runs roughly from March to October, that translates into:

Period	Average water (approx.)	Recommendation
March–April	13–14 °C	5/4 mm or a very warm 4/3, boots recommended
May	about 15 °C	4/3 mm, boots if needed
June–July	approx. 16–17 °C	4/3 mm
August–September	approx. 17–19 °C	4/3 mm, or 3/2 mm on sunny, still days
October	about 16 °C	4/3 mm

A shorty is the exception in Galicia, even in August. If you only want to buy one suit for Spain and Portugal, a good 4/3 chest-zip will cover you nearly every time. For more about the region and timing, read surfing in Galicia and the best time to surf in Spain.

What about Portugal and France?

Portugal (Peniche, Ericeira): around 14–18 °C all year. A 3/2 often does the job in summer; in winter a 4/3 is a must.
Algarve (Sagres): slightly warmer, around 19–20 °C in late summer, when a springsuit can work.
France and the Basque Country: roughly 21–23 °C from July to September, so a shorty or 2 mm suit is possible. In spring and late autumn you'll want a 4/3.

For a full country comparison, see surf camp in Spain vs Portugal vs France.

How a wetsuit should fit

A wetsuit only keeps you warm if it fits snugly. If cold water floods in on every duck dive and washes away the warm layer, even the thickest suit won't help. When trying one on:

Tight but not restrictive. On land it may feel almost too small. Neoprene gives a little in the water.
No wrinkles or air pockets in the back, under the bum or behind the knees.
Neck and wrists seal well without choking you.
Shoulders free: do the paddling motion with your arms stretched out. If it pulls hard, the suit is too small or too thick.
Squat: crouch as you would when popping up. If it pinches in the crotch, try another size.

Size charts are usually based on height, weight and chest measurement, and they differ between brands. Try suits on whenever you can.

Back zip, chest zip or zipless?

Zip type	Pros	Cons	Best for
Back zip	Easy to get in and out of, often cheaper	More water entry at the back, slightly less flexibility	Beginners, rental suits, warm water
Chest zip	Better seal, warmer, more flexible back	Takes some practice to put on	Most Atlantic surfers
Zipless	Very flexible, few seams	Harder to get into, can stretch out sooner	Experienced surfers, warmer water

Seams matter too. Flatlock stitching lets a little water through and suits warm water. For cooler water, glued and blind-stitched seams, often taped as well ("sealed and taped"), are much warmer. From 4/3 upwards, look for those.

Should you buy or rent a wetsuit?

As a beginner you don't need to own a wetsuit. Surf schools and camps rent suits in the right size and thickness for local conditions. On the Semesterkur surf camp in Galicia (booking pages are in German), your board and wetsuit are provided for the 4-day surf course with Abel Lago Watersports.

Buying your own makes sense if:

you surf more than once or twice a year,
you have a home break (Cornwall, the North Sea, the Dutch coast),
you'd rather not wear a suit that plenty of others have worn before you,
you're between sizes and rental suits never quite fit.

For a first suit, a 4/3 mm chest-zip full suit is usually the best all-rounder. It covers the Atlantic from Galicia to Portugal for most of the year and northern European waters in summer. For everything else to bring, see the surf trip packing list.

How to look after your wetsuit

With proper care a decent suit lasts several seasons:

Rinse in fresh water after every session, inside and out. Salt and sand make neoprene brittle.
Dry it in the shade. UV light damages neoprene. Dry the inside first, then turn it out.
Use a wide hanger or fold it over a bar at the waist. Thin wire hangers dent the shoulders.
No hot water, washing machine or tumble dryer. If needed, hand-wash with a wetsuit shampoo.
Look after the zip: rinse out sand and use a bit of zip wax now and then.
Don't leave it in a hot car. Heat damages the material and glued seams.

You can fix small tears yourself with neoprene glue before they spread.

Staying warm and safe in cold water

Cold water saps energy. When you're cold you paddle worse, react more slowly and have less fun. Signs it's time to get out: shivering that won't stop, numb fingers, lips turning blue or trouble concentrating. Eat something before you surf, stay hydrated and change quickly afterwards. A changing robe or poncho and a flask of tea make a real difference in Galicia, even in summer.

For staying safe in the line-up, read our guide to surf etiquette. For choosing your board, see the beginner surfboard size guide.

Conclusion: which wetsuit thickness do you need?

Check the water temperature at your destination first and the air temperature second. For Galicia and Portugal a 4/3 is almost always right; in France a thinner suit will do in high summer. A snug fit matters far more than a millimetre either way. If you'd rather start without your own kit, the Galicia surf camp includes wetsuit, board and lessons. More answers are in the surf FAQ (in German).

Last updated: November 2026

Wetsuit Thickness Guide: Chart by Water Temperature 2027

In a minute

What do the numbers on a wetsuit mean?