Your Cart is Empty

April 18, 2021 5 min read

Factors Determining the Wetsuit Thickness

The type and thickness of the wetsuit you wear when going diving will be determined by three things; the temperature of the water and how deep you intend to dive, and how long you intend to stay underwater.


The Water Temperature

Wetsuits are recommended by the Professional Association of Diving Instructors (PADI). Heat escapes the body 25 times faster in water as compared to air. Without a suitable wetsuit, your body would lose heat faster than it can produce, and hence you run the risk of hypothermia.


Diving Depth

The deeper you dive into the water, the colder the temperature would get. This is because only a layer of water on the surface is heated by the sun. The warm lighter water tends to stay on top while the cooler, denser water sits at the bottom. The separation between these two layers is called a thermocline, and water gets colder faster when you cross it. The thermocline has a wide range of 50m to 1000m depending on your geographical location, the depth of the water, and the heat of the sun.


When going diving in the ocean or lake, you need to know the depth of the thermocline to help you pick the appropriate wetsuit.


Duration and Frequency of Diving

The longer you are in the water, the more heat you will lose and the colder you will get. To stay warm, reduce the lengths of dives and have out-of-water breaks to let your body return to normal temperature. Alternatively, if you have to stay longer in water, you will need to get a thicker wetsuit.


How do wetsuits work?

Wetsuits are made of neoprene, a flexible rubber material that is permeable or spongy. The material has small air-filled spaces that are occupied by water when submerged, creating a thin layer of trapped water. The thin layer of water is heated by our bodies and acts as insulation from the cooler water outside the suit. This insulation by water mechanism reduces heat loss and keeps us warm.


Thinner suits will lose efficiency faster in cold waters. Thicker wetsuits in warm water will be unnecessary; they will, in fact, restrict your speed of movement and ability to make quick turns due to all that weight. Thicker suits make you clumsy and tired faster during a dive.


Water pressure increases the deeper you dive, and the small spaces in the wetsuit are compressed. Their capacity to house water and prevent rapid heat loss is reduced, and the wetsuit gets less efficient as a result. If you plan to dive deeper and longer, you should consider the thickest wetsuit available, the 7mm wetsuit. Other common wetsuits for temperate and warm temperatures are the 5mm and 3mm wetsuits, respectively.


7mm Wetsuit for Cold Water Diving

Waters with temperatures ranging from 45 to 60 degrees Fahrenheit (8 to 15 degrees Celsius) are considered cold waters. The 7mm wetsuit is appropriate for use when diving at these temperatures. You don't have to go measuring the water to know, check the weather conditions. If there is chronic rain or snowfall, the water would most likely fall in this range, and you should wear a 7mm wetsuit. You can also rely on information from other divers or the local weather to know what type of suit to wear when going diving at a certain location.


7mm Wetsuit


To keep comfortable in cold waters, you will need diving accessories to go with your wetsuit. These include; an oversuit worn over the wetsuit to further shield you from the cold water, a vest over your chest area, a hood that covers the head completely, and gloves. There are, of course, other accessories, and you should only put on a minimum that guarantees your comfort without making you heavier. Cold water wetsuit and accessories: 7mm fullsuit + over-suit + hood + gloves.


Other Factors to Consider

Your body loses or retains heat depending on the state of your health, your age, gender, amount of body fat and body surface area to volume ratio, and your metabolic rate.



Younger people have more active body processes. They burn food faster and produce more heat to keep them warm. The metabolic rate drops with an increase in age. Older divers, therefore, need the 7mm wetsuit more as compared to their younger counterparts.



Women record a faster temperature drop in water than men because of their lower metabolic rates. Women's energy needs are at a minimum because they have fewer muscles than men. Muscular cells spend more energy producing more body heat as a result. Women, therefore, need the 7mm wetsuit more as compared to their male counterparts.


Weight/ Fat composition

Fatty layers beneath the skin act as primary insulation against heat loss. Therefore, a skinnier person would lose more heat faster in water because they have thinner fatty layers compared to plumier people. The 7mm wetsuit would offer great comfort for skinnier people keeping them warmer for longer.


Surface Area to Volume Ratio

With more of your body exposed to water, you are likely to lose heat faster. Children have a greater surface area to volume ratio than full-grown adults. A 7mm wetsuit is a must-have for children, especially those with petite bodies.


These factors form two categories of divers; warm divers and diver prone to cold. Warm divers have nothing to worry about; they can adorn their 7mm wetsuits during their escapades in cold waters. Divers prone to cold, on the other hand, may need to accessorize. In summary, a 7mm suit is a must-have when diving in cold or near waters for the following categories of people;-

  • Older people
  • Women and children
  • People who are considered underweight
  • Those with underlying health conditions affecting their metabolic rate



A 7mm wetsuit is not only good but necessary for water temperatures below 15 degrees Celsius. It could be dangerous to go diving in cold waters without proper insulation. You should also avoid diving altogether if you are not in a perfect health condition or if you lack information about the conditions of your chosen diving location. This includes the temperature of the water, the depth of the water body, and the thermocline. Otherwise, have exciting and safe diving!


Also of Interest: 


Liz H.
Liz H.

Leave a comment

Comments will be approved before showing up.

Also in Buy4Outdoors Blog

Are Triathlon Wetsuits Different?
Are Triathlon Wetsuits Different?

May 15, 2021 4 min read

If you are a triathlon enthusiast, chances are you like wetsuits. The attire not only keeps cold water from paralyzing your legs and arms and sinking before you get to the shore, but they also enhance swimming speed by up to 7%, which is more than enough to give a triathlete a 70-to-90-meter edge over other suitless competitors.

Read More
How Many Life Jackets Must Be on a Boat?
How Many Life Jackets Must Be on a Boat?

May 09, 2021 5 min read

All passengers on small vessels are obliged to wear life jackets. Be sure to wear a life jacket when you board a small boat! Wearing a life jacket will more than double your survival rate! For compliance with U.S. Coast Guard rules, a vessel must have U.S. Coast Guard Approved lifejackets for everyone aboard.

Read More
2021 Best Plus Size Wetsuits for Big and Tall Men
2021 Best Plus Size Wetsuits for Big and Tall Men

May 07, 2021 6 min read

Luckily, several manufacturers consider the needs of all surfers, regardless of their body types, when making wetsuits. With the best plus-size wetsuit, you can go scuba diving, swimming, surfing, and paddling comfortably and safely. Below is a list of plus-size wetsuits for big and tall men widely available and affordable.

Read More