Wetsuit Thickness Guide

Wetsuit thickness guide

Picture this: it’s February, and you’re standing on the edge of the Atlantic Ocean, ready to plunge into its depths, surfboard in hand, with perfect waves peeling ahead of you. One thing you want to know for sure; ‘Is my wetsuit up to the job?’  

How long will you last in the frigid waters before making a quick retreat to the cosy pub around the corner? Well, before you take that leap, let’s talk about wetsuit thickness and how many millimetres you should be wearing.

Whether you’re a seasoned watersports enthusiast or a novice dipping your toes into the waves, understanding wetsuit thickness is vital for maximising your enjoyment and comfort in the water.

In this wetsuit thickness guide, you’ll learn how to make informed choices about what wetsuit works best for different water temperatures and our varied UK seasons.

What is wetsuit thickness?

Wetsuit thickness refers to the measurement of the neoprene material used in the wetsuit. It indicates the width of the layer that provides insulation and protection from the cold water.

Measured in millimetres, wetsuits typically have varying thicknesses in different areas of the suit to optimise flexibility, buoyancy, and warmth. 

For example, a 3/2mm wetsuit has a 3mm torso thickness with 2mm on the arms/legs.

A 5/4/3mm wetsuit has a 5mm torso, 4mm legs, and 3mm arms. 

How thick should my wetsuit be?

In this section, we recommend wetsuit thickness based on water temperature, rather than on destination or season of the year. 

That way, no matter where you are headed in the world, you can check the water temperature in advance and pack the correct suit. 

It might be winter steamer season here in the UK, but balmy bathing on your exotic break in Indonesia (NICE!).  

Warm Water  (20°C +)

Recommended wetsuit thickness: no suit – 1mm

At these warm water temperatures, it is not strictly necessary to wear a wetsuit. You might be comfortable in a swimsuit, or board shorts and a rash vest instead.

However, a variety of super thin 1mm neoprene tops and suits are available that offer enhanced sun protection and comfort when laying on the board. Pro tip: an ultra thin wetsuit will help to keep all your bits in place when taking a spin in the washing machine!

Mild Water (18-24°C)

Recommended wetsuit thickness: 2-3mm

In mild water, a wetsuit with 2-3mm thickness will provide some insulation while still allowing freedom of movement. This is the lower end of the wetsuit thickness guide and a shorty or a full wetsuit (long-sleeved and long-legged) can be used depending on personal preference.

Cool Water (12-18°C)

Recommended wetsuit thickness: 3-4mm

In cool water, a wetsuit with 3-4mm thickness is ideal for maintaining warmth during longer periods in the water. A full-length wetsuit is recommended to cover the entire body. 

Cold Water (9-12°C)

Recommended wetsuit thickness: 4-5mm

In cold water, a wetsuit with 4-5mm thickness is necessary to provide insulation and protect against the low temperatures. A full wetsuit with sealed seams and additional features like a hood may be required for optimal warmth. To maintain mobility in very cold water, some watersports users may opt for a 4-5mm wetsuit accompanied by accessories instead of a 6mm or more.

Very Cold Water (below 9°C)

Recommended wetsuit thickness: 5mm (or thicker)

In very cold water, a wetsuit with 6mm thickness is essential to prevent hypothermia. A full wetsuit with additional accessories like booties and gloves are often needed to protect against extreme cold.

Wind Chill 

Remember, we spend a lot of time sitting and standing on our boards while surfing, windsurfing and SUPing. 

The above recommendations offer a solid foundation for choosing a suit, but don’t forget to make allowances for wind chill. On a perfectly still day, with the sun on your face, you could feel comfortable in less neoprene than when it’s blowing a hooley, even if the water temperature is the same.   

With this in mind however, remember to always dress for the coldest element, even if this results in the odd sweaty session. 

With no wind and a nice ambient air temperature, you might feel warm charging around doing your sport, but if something were to go wrong (broken/lost equipment or an unexpected change of conditions) and you have to spend an extended time in the water, you’ll need to know your wetsuit will protect you from getting cold.  

We’ll cover more on air temperature in the next section…

What thickness wetsuit do I need in the UK?

Wetsuit thickness is important because it directly affects the insulation and warmth provided by the suit. Thicker wetsuits allow you to stay in cold water for longer periods of time. 

This is invaluable for UK watersports lovers who often have to deal with water temperatures lower than 10 degrees.

In the UK, we don’t often have to worry about utterly freezing water, nor do we have the luxury of enjoying tropical waves either! 

Though we may be a small Island nation, the difference in our geographical extremities can be striking. Summer suits in Cornwall can still mean full winter steamers in the Orkney Islands!

However, it’s worth remembering that personal preferences, tolerance to cold, and activity level can vary from person to person. 

So it’s important to consider factors like wind chill and duration of water exposure when looking at a wetsuit thickness. 

This guide below explores the different seasons based on UK averages. 

Spring in the UK

Average air temperature: 10-15°C

Average sea temperature: 9-12°C

Wetsuit thickness: 4-5mm

Wetsuit accessories: Boots and hood on the colder days

In early spring, the water is still relatively cool, so a wetsuit with 4-5mm thickness is recommended to provide insulation and protection against the low temperatures. As the water warms over the months, you can drop any accessories or choose a thinner wetsuit.

Summer in the UK

Average air temperature: 15-25°C

Average sea temperature: 15-18°C

Wetsuit thickness guide: 2-3mm

Wetsuit accessories: None

In summer, the water and air temperatures are relatively warm, and many people choose to forego wetsuits altogether. However, if you feel the need for added warmth or protection, a wetsuit with 2-3mm thickness will be suitable.

Autumn in the UK

Average air temperature: 10-15°C

Average sea temperature: 12-15°C

Wetsuit thickness guide: 4-5mm

Wetsuit accessories: Boots and hood on the colder days

Autumn sees a decline in both air and sea temperatures, particularly late in the season. A wetsuit with 4-5mm thickness is recommended from October onward. A full wetsuit with sealed seams and additional accessories can be beneficial for extended periods in the water or during poor weather.

Winter in the UK:

Average air temperature: 2-8°C

Average sea temperature: 7-10°C

Wetsuit thickness guide: 5-6mm

Wetsuit accessories: Boots, hood and gloves

Winter brings the coldest temperatures to the UK. It’s essential to wear a wetsuit with 5-6mm thickness or more to keep you warm in the frigid water and bitter air temperatures. A full wetsuit with sealed seams, a hood, booties, and gloves are highly recommended for optimal warmth and safety.

Should you always choose the warmest wetsuit?

Choosing the warmest wetsuit on the market is not always necessary or recommended. When using this wetsuit thickness guide, you should select suits based on the water temperature and the individual’s comfort level. 

Wearing a wetsuit that is too thick for the conditions can lead to overheating, a lack of manoeuvrability, and discomfort. It’s all about finding that Goldilocks zone where warmth meets practicality!

What else affects wetsuit warmth?

The best wetsuit depends on several factors, including personal style, budget, intended use, and the specific water and weather conditions you will be facing. 

It’s advisable to try on different wetsuit brands and models to find the one that fits, provides adequate warmth, and meets your specific requirements. Generally, a higher-priced wetsuit will perform better and last longer. 

A higher priced wetsuit will be made from more technical neoprene and often offer  desirable flexibility in addition to superior warmth.  

However, you can still find some excellent mid-range models and make use of low-season sale prices.

Keep warmer with wetsuit accessories

When looking at this wetsuit thickness guide, don’t forget to account for accessories. 

This can have a huge impact on your comfort and warmth in the water. If you select a good combination of accessories, you’ll be much better equipped to deal with those ultra low water temperatures. 

Hood: A wetsuit hood helps keep your head warm in cold water and provides additional insulation. It prevents heat loss from the head and can be crucial in extremely cold conditions.

Gloves: Wetsuit gloves protect your hands from cold water and loss of dexterity. They also offer additional grip and protection against abrasions and scrapes.

Booties/Neoprene Socks: Wetsuit booties or neoprene socks keep your feet warm and protect them from sharp objects, rocks, or rough surfaces. They provide insulation and enhance comfort while ensuring better traction on slippery surfaces.

Wetsuit Vest/Top: A wetsuit vest or top can be worn underneath a wetsuit or on its own in warmer conditions. It provides extra insulation to the core and keeps your upper body warm without restricting arm movement.

About the author

Lois O'Connell

Surfing, sailing, windsurfing, wakeboarding, skiing, snowboarding, mountain biking, trail running...Lois has travelled the world competing and teaching in the outdoor industry. Now based on the South Coast of England, she continues to push herself in adventure sports and shares a lifetime of passion with us at Watersportspro.

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