Wetsuit Temperature Guide

Your wetsuit can make the difference between a great underwater adventure and a prematurely ended dive because of discomfort or even hypothermia. If you are serious about diving, you need the right wetsuit to keep you warm and make your underwater adventure one worth remembering.

Here at Divers Supply, we have a wide range of wetsuits from trusted and reputable brands like Aqua Lung, Cressi, Henderson, Mares, Neosport, Sea Elite, Seac, Sharkskin, and ScubaPro. You will find wetsuits of any thickness and design to match your diving expectations.

How Wetsuits Work: The Science Behind Staying Warm

Wetsuits don't actually keep you dry. Instead, they work on a simple but effective principle.

1. Thermal Insulation: Wetsuits are made from neoprene, a synthetic rubber containing thousands of tiny nitrogen gas bubbles that insulate your body from the outside world.
2. Trapped Water Layer: A thin layer of water enters the suit and is trapped between your body and the neoprene. Your body warms this water, creating a thermal barrier against the colder water outside.
3. Reduced Water Circulation: The wetsuit is properly fitted to minimize the amount of water that flushes in and out. The little water that has entered is kept warm and insulates your body from the outside water temperature.
4. Heat Retention: The more neoprene (thicker wetsuit), the better the insulation and heat retention. If you dive in very cold waters, you want a thicker wetsuit than if you choose warmer seas.

Understanding Wetsuit Thickness

How Thickness is Measured

Wetsuit thickness is measured in millimeters (mm) and is often expressed as two or three numbers, for example:

• 3/2mm: The first number (3mm) represents the thickness around the torso, while the second number (2mm) indicates the thickness in the extremities (arms and legs).
• 5/4/3mm: In three-number formats, the measurements represent the torso, legs, and arms respectively.

Thinner neoprene in the extremities helps you stay more flexible and move your arms and legs more comfortably. The core of your body remains warm with maximum thermal protection.

Temperature Ranges and Recommended Thickness

Remember that these are general guidelines. Your personal cold tolerance, body composition, and activity level will affect your comfort in different temperatures.

Assessing Diving Conditions: Beyond Water Temperature

While water temperature is the primary factor in wetsuit selection, other environmental factors also come into play.

Environmental Factors

Wind Chill

Strong winds can rapidly cool your body before and after dives, especially when wet. If you are diving in windy conditions, you should wear a wind-breaking layer or thicker wetsuit.

Air Temperature

If there's a significant difference between water and air temperatures, take it into consideration. Large temperature differences can cause thermal shock when entering or exiting the water.

Personal Factors

Metabolism

Some people naturally run "hot" or "cold." Pay attention to your personal comfort levels in different temperatures and adjust your wetsuit thickness accordingly.

Body Composition

People with higher body fat percentage have better natural insulation. Leaner individuals may need thicker suits or additional layers for the same conditions.

Experience

New divers often need more thermal protection as they learn to relax underwater. Tension and anxiety can increase cold sensitivity and reduce your body's efficiency at maintaining heat.

Age

Older divers may need more thermal protection as circulation efficiency decreases with age. Consider adding 1-2 mm of thickness if you are over 50 or have circulation issues.

Diving Duration

Longer dives require more thermal protection as your body gradually loses heat over time. Add an extra millimeter of thickness for dives lasting over an hour, no matter the water temperature.

Depth

Water temperatures decrease with depth. Calculate the coldest temperature you will encounter. Most recreational dives will experience a temperature drop of 2-4°F (1-2°C) from surface to maximum depth. Account for these temperatures when you buy a wetsuit from Divers Supply.

Activity Level

More active diving generates body heat, while photography or slow exploration may require thicker protection. Adjust your wetsuit thickness based on your diving style.

How a Wetsuit Should Fit

Your wetsuit should fit properly, and feel like a second skin—snug but not constricting. Consider the guidelines below for a perfect fit:

Fit Guidelines

Length

When you stand upright, there should be no excessive bunching of material. The wetsuit should extend fully without restricting your movement at your joints.

Torso

The wetsuit should feel snug across your chest and back with no large air pockets. You should feel a little compression throughout your core.

Shoulders

You should be able to raise your arms above your head with some resistance, but without excessive strain. Imagine you are swimming and moving your arms above your head: it should feel comfortable.

Legs

Your wetsuit should extend fully to your ankles without excessive pulling in the crotch area. When you bend your knees, you shouldn't feel any significant restriction.

Arms

As for the arms, the wetsuit should extend to your wrists without leaving gaps or riding up on your arms. Arm movement should feel smooth without binding at the elbows.

Neck

The neck should fit comfortably without choking or leaving large gaps where water can flush in, otherwise you are losing the whole insulation effect. A proper neck seal prevents cold water flush.

Mobility Test

Simulate swimming motions and check that you can move without severe restriction. To better assess mobility, try a few knee bends, shoulder rotations, and reaching motions.

Common Fit Issues

Too Loose

Excessive water circulation dramatically reduces thermal efficiency. Signs include billowing material, large gaps at extremities, or feeling cold water "flushing" through the suit.

Too Tight

Restricted breathing or circulation can be uncomfortable and potentially dangerous. Look for numbness, discoloration in extremities, or difficulty taking deep breaths.

Pressure Points

Pressure points can lead to discomfort, chafing, and reduced circulation. Pay special attention to the neck, underarms, and behind the knees, where pressure points commonly occur.

Types of Wetsuits: Lengths and Styles

Wetsuits come in many configurations to suit different diving conditions and preferences.

By Length

Full Suit (Steamer)

Steamers completely cover arms and legs for maximum coverage and warmth. They are the most common style for serious diving in cool to cold water conditions. Full suits provide the most consistent thermal protection.

Shorty

The shorty features short arms and legs, ideal for warmer waters or as a layering piece. Shorties extend to mid-thigh and elbow and provide core warmth with extremity freedom.

Long John/Jane

The Long John/Jane has full-length legs but no arm coverage. It balances warmth and upper body mobility. It’s popular in tropical diving where you want your arms free but still need leg protection.

Jacket

The jacket covers the torso and arms but not the legs. It’s often used in combination with a bottom piece. This modular approach can customize thermal protection based on conditions.

Farmer John/Jane

This has full-length legs and a sleeveless top. It’s popular for water sports requiring arm mobility and is often used in layered configurations for cold-water diving.

Tops/Bottoms

Separate pieces can be worn individually or combined for customized protection. If diving is your passion and you explore year-round, they are good for transitioning between seasons.

Hooded Suits

Hooded suits include an attached or removable hood for additional head protection. They are necessary if you dive in water below 60°F (15°C) as significant heat loss occurs through the head.

Specialty Designs

Besides the above, you can also find specialty designs to fit any need.

Dive-Specific

Wetsuits for diving are optimized for scuba diving. They have reinforced knees and shoulders and additional features for gear attachment. These suits often have extra padding in high-wear areas and may incorporate pockets or mounting points for accessories.

Freediving

Freediving wetsuits are usually more flexible with smooth exteriors to reduce drag. They prioritize hydrodynamics and often use higher-grade materials for improved stretch and comfort.

Surface Sports

Surface sports wetsuits are designed for activities like surfing with paddling-friendly features and abrasion resistance. These suits include reinforced panels in paddle zones and more flexible materials across the shoulders and arms.

Wetsuit Construction: Technical Features

Seam Types

The stitching method significantly impacts a wetsuit's warmth and durability:

1.           Overlock (Flatlock) Seams:

• Appearance: Visible flat stitching on both inside and outside.
• Warmth: Least warm as water can penetrate through the stitch holes.
• Flexibility: Highly flexible and comfortable.
• Best for: Warmer water (65°F/18°C and above).

2.           Glued and Blind-Stitched (GBS) Seams:

• Appearance: Seams are glued first, then stitched from the inside without penetrating the outer surface.
• Warmth: Better water resistance as stitching doesn't penetrate completely through the neoprene.
• Flexibility: Good flexibility with better warmth.
• Best for: Moderate to cold water (down to about 55°F/13°C).

3.           Sealed Seams:

• Appearance: GBS seams with an additional sealant tape or liquid sealant applied to the interior.
• Warmth: Excellent water resistance.
• Flexibility: Slightly reduced compared to GBS alone.
• Best for: Cold water diving (below 55°F/13°C).

4.           Fluid-Sealed (Liquid Taped) Seams:

• Appearance: GBS seams with liquid rubber or waterproof material applied to seal stitch holes.
• Warmth: Excellent water resistance.
• Flexibility: Can maintain good flexibility depending on the sealant used.
• Best for: Very cold water diving.

5.           Welded Seams:

• Appearance: No visible stitching, seams are fused together.
• Warmth: Maximum water resistance without stitch holes.
• Flexibility: Can be very flexible with modern materials.
• Best for: Extremely cold conditions.

Zipper Systems

Zippers need to balance accessibility with water resistance:

1.           Back Zippers:

• Traditional design with a long vertical zipper down the back.
• Pros: Easier to get on and off independently, familiar design.
• Cons: More water entry points, potentially less flexibility in the back.

2.           Chest Zippers:

• Horizontal or diagonal zipper across the chest/shoulder area.
• Pros: It reduces water flushing and provides more flexibility in the back.
• Cons: May require assistance to put on, learning curve for new users.

3.           Zipperless Entry Systems:

• Uses overlapping neoprene panels instead of zippers.
• Pros: Maximum flexibility, no zipper failure points, reduced water entry.
• Cons: More difficult to get on and off, requires assistance.

4.           Two-Piece Systems:

• Separate top and bottom pieces that overlap.
• Pros: Versatility, potentially easier to put on.
• Cons: Potential for water entry at the overlap point, may shift during use.

Neoprene Technology and Innovations

Modern wetsuits are made with advanced materials and technologies.

1.           Air-Cell Neoprene:

• Features millions of tiny air bubbles for improved insulation.
• Benefits: Lighter weight, better warmth-to-thickness ratio.

2.           Super-Stretch Neoprene:

• Incorporates elastane or other stretchy materials into the neoprene.
• Benefits: 200-300% more stretch than traditional neoprene, better comfort and mobility.

3.           Thermal Linings:

• Interior linings like plush "wool-like" materials, titanium, aluminum, or infrared-reflecting layers.
• Examples: Henderson's Thermoprene.
• Benefits: Better heat retention, faster drying, additional warmth without added thickness.

4.           Slick-Skin (Smooth Skin) Exterior:

• Non-textured, smooth outer surface.
• Benefits: Repels water, reduces wind chill, and increases thermal efficiency.
• Best for: Very cold conditions or surface intervals in windy conditions.

5.           Hydrophobic Neoprene:

• Treated to absorb less water.
• Benefits: Lighter when wet, maintains flexibility, and insulates properties better.

6.           Sustainable Neoprene Alternatives:

• Limestone-based neoprene instead of petroleum-based.
• Yulex natural rubber derived from sustainable sources.
• Benefits: Reduced environmental impact, often comparable or superior performance.

Caring for Your Wetsuit

To extend the life of your wetsuit and keep its thermal properties:

1. Rinse thoroughly with fresh water after every use, especially after saltwater diving.
2. Wash occasionally with neoprene-specific soap (never use detergents or regular soaps).
3. Dry in shade and hang on a wide hanger, away from direct sunlight or heat sources.
4. Store properly on a wide hanger in a cool, dry place away from direct sunlight.
5. Don’t fold it for long periods to prevent permanent creases.
6. Inspect regularly for tears or delamination and repair with neoprene cement.

Get the Right Wetsuit from Divers Supply

Our Divers Supply collection of wetsuits includes dozens of models from reputable manufacturers. When you are ready to buy a wetsuit, consider water temperatures, personal factors, and the technical features that you are looking for.

You will find excellent wetsuits with varying thickness levels and seam construction features. Remember that the best wetsuit is one that lets you focus on the beauty of the underwater world rather than on being too cold (or too warm).

We know we have the right wetsuit for your diving experience, whether you are diving in tropical reefs or exploring cold waters. Our certified professionals, 40 years of vast experience, manufacturers’ warranty, and customer satisfaction team set us apart from the competition. Check out our shop, dive into our collection, and get started on your diving adventures today!