What Wetsuit Thickness Do I Need? Water Temperature Chart
Quick answer
Choose your wetsuit by water temperature. As a rough guide: boardshorts or a rash vest above about 24°C (75°F), a 2 mm shorty or springsuit around 18-21°C (64-70°F), a 3/2 full suit around 15-18°C (59-64°F), a 4/3 around 12-15°C (54-59°F), and a 5/4 with hood, boots and gloves below about 12°C (54°F).
In this guide
The right wetsuit thickness depends mostly on water temperature. As a rough guide, you can surf in boardshorts above about 24°C (75°F), you want a 3/2 full suit around 15-18°C (59-64°F), a 4/3 around 12-15°C (54-59°F), and a 5/4 with hood, boots and gloves below that. Wind, air temperature and how cold you personally run can shift each step by a few degrees.
What “4/3” and “3/2” mean
Wetsuit thickness is written as two numbers in millimetres:
- The first number is the neoprene thickness on the torso.
- The second number is the thickness on the arms and legs.
So a 4/3 is 4 mm on the body and 3 mm on the limbs. A 3/2 is 3 mm and 2 mm. A 5/4 is 5 mm and 4 mm. Some suits list three numbers, such as 5/4/3, where the third figure is an even thinner panel in high-movement areas like the shoulders or knees.
Why not just make everything thick? Because you paddle with your arms. Thinner neoprene on the shoulders and arms bends more easily, so you tire less. Your core loses heat that matters most, so it gets the extra insulation.
A wetsuit works by trapping a thin layer of water between the suit and your skin, which your body then warms up. The better the fit, the less that warm layer gets flushed out by cold water.
Water temperature to wetsuit chart
Use this as a starting point. Wetsuit ranges overlap, and different surfers draw the lines a little differently.
| Water temperature | What to wear |
|---|---|
| Above 24°C (above 75°F) | Boardshorts or swimsuit, rash vest for sun and rash protection |
| 21-24°C (70-75°F) | Rash vest or neoprene top; 2 mm shorty on windy days |
| 18-21°C (64-70°F) | 2 mm shorty or springsuit, or a 2 mm full suit |
| 15-18°C (59-64°F) | 3/2 full suit |
| 12-15°C (54-59°F) | 4/3 full suit, boots optional |
| 9-12°C (48-54°F) | 5/4 full suit with hood, boots and gloves |
| Below 9°C (below 48°F) | 5/4 or 6/5 hooded suit, thick boots and gloves |
A shorty has short arms and short legs. A springsuit usually has short legs and either short or long arms. Both are ideal for that in-between water that is too cool for boardshorts but too warm for a full suit.
How wind and personal tolerance shift the chart
Water temperature is only part of the picture.
Wind chill
A cold wind pulls heat off you every time you sit up between sets. Strong wind, especially cold onshore wind, can make a 3/2 day feel like a 4/3 day. On a windy session, consider going one step warmer than the chart, or adding a hood or a neoprene top under your suit.
Air temperature and sun
Warm sun and still air make a thinner suit comfortable. Overcast skies and cold air do the opposite. Early morning sessions usually feel colder than the same water in the afternoon.
Your body and your session
- Lighter or leaner surfers often feel the cold sooner.
- Long sessions need more warmth than a quick hour.
- Beginners spend more time sitting or standing in the whitewater and can get colder than experienced surfers who paddle constantly.
- Some people simply run cold. If that is you, size up in thickness and do not feel bad about it.
As a rule: if you are shivering, you are not having fun and you are not surfing well. Cold also drains energy and slows your reactions, which matters around rips and crowded line-ups. Read up on rip currents if you surf in cold, powerful water.
Fit tips
A warm suit that fits badly is a cold suit. When you try one on:
- Aim for snug everywhere. It should feel like a second skin with no baggy folds at the lower back, armpits or behind the knees.
- Check the neck. The seal should be close but should not choke you or rub badly.
- Test the shoulders. Raise your arms overhead and mimic paddling. If it pulls hard across the shoulders, try another size or brand cut.
- Squat down. The crotch should not hang low, and the knees should not feel strained.
- Wrists and ankles should sit close to the skin so water does not rush in.
Wetsuits loosen slightly when wet, but do not rely on that to fix one that is clearly too small. Sizing varies between brands, so try more than one if you can.
Back-zip vs chest-zip
| Style | Pros | Cons |
|---|---|---|
| Back-zip | Easy to get in and out of; often cheaper | Long zip lets more water in; back panel less flexible |
| Chest-zip | Less flushing, usually warmer; more flexible back | Harder to put on, especially at first |
| Zipless | Very flexible and warm | Tricky to get into; needs a precise fit |
For a first suit, back-zip is perfectly fine in mild water. In colder water, chest-zip suits are the more common choice because keeping water out matters more.
Boots, gloves and hoods
Accessories extend the range of your suit:
- Boots (usually 3-7 mm) keep feet working in cold water. Your feet are what you stand on, so numb feet mean sloppy surfing.
- Gloves (usually 2-5 mm) help when your hands go numb, though thick gloves make paddling feel different.
- Hoods cut heat loss from your head and help protect your ears from repeated cold water and wind.
Wetsuit care
A good suit can last several seasons if you look after it:
- Rinse in fresh water after every session, inside and out.
- Dry it inside out, in the shade. Sunlight breaks down neoprene over time.
- Hang it over a thick hanger or fold it over a rail at the waist, not by the shoulders, which can stretch them.
- Do not leave it wet in a bag or a hot car for hours.
- Use wetsuit shampoo occasionally rather than harsh detergents.
- Fix small tears early with neoprene glue before they spread.
Putting it together
Check the water temperature first, then adjust for wind, air temperature and how long you plan to stay out. If you are torn between two thicknesses, the warmer one is usually the safer pick, especially while you are learning. Surfast’s forecast includes water temperature where it is available, which makes it easier to decide between your 3/2 and your 4/3 the night before. For the rest of the picture, see how to read a surf forecast.
Frequently asked questions
It means the neoprene is 4 mm thick on the torso and 3 mm thick on the arms and legs. The thicker core keeps you warm, while the thinner limbs let you paddle more freely.
As a rule of thumb, a 3/2 full suit suits water of roughly 15-18°C (59-64°F). Many surfers stretch it a few degrees either side depending on wind and how cold they run.
Most surfers add boots somewhere around 12-14°C (54-57°F) and add a hood and gloves once the water drops to roughly 10-12°C (50-54°F) or below. Cold wind brings that point forward.
Chest-zip suits usually let less water in, so they tend to be warmer and more flexible across the back. Back-zip suits are easier to put on and take off.
Snug everywhere, like a second skin, with no loose folds or air pockets, but not so tight that it restricts breathing or shoulder movement when you paddle.