Diving Wetsuit Water Temperature Guide And Chart

Sea temperature chartNote: There is another wetsuit thickness/water temeprature guide and chart on this website that I suggest you check out – most of the things written there are very usefull to know. Since diving is a bit specific when it comes to wetsuits and temperature I wrote another guide which is dedicated solely to diving wetsuits. Here it is…

The temperature of the water around you will determine what wetsuit you will need for diving and how thick it will need to be. This temperature depends on the location of your dive as well as the time of year. Other factors, like the depth of your dive, will also influence the water’s temperature. Here are a few main factors and facts to consider when talking about diving wetsuit thicknes. Some of them are also the reason why diving wetsuits deserve their own temperature guide:

Water Temperature

Well…duh. This one is pretty obvious. The main difference when it comes to diving is that you are completely submerged and surrounded by water during your dive. According to PADI water pulls heat out of your body around 25 times faster than air.

Depth Of Your Dive

Deeper water tends to be colder (termocline). But not only that – when you dive deeper that pressure increases and neoprene compresses. The air bubbles in the neoprene that are the main insulators get smaller. So neoprene looses thermal qualities with depth. As one of our readers commented: “A 3mm neoprene suite at the surface will lose 50% efficiency at depth of 10 meters. At 20 meters is becomes only 30% efficient, at 40 meters (your recreational depth) 25% efficient when compared to the surface (1 atmosphere). So if you purchase 3mm wetsuit, it becomes 1mm equivalent at depth of 30 meters / 100 feet.” A rule of thumb is to subtract about 5 degrees for a 30m / 100 ft deep dive from the surface temperature. But of course – this is nowhere near to be an exact and accurate number. Conditions vary from location to location. In some places water temperature can be the same from top to bottom in other termocline can be quite obvious.

Activity Level

If you are active during your dive you will generate heat and fell less cold. If you are mostly stationary, with slow movements to keep the heartrate, breathing and air consumption down – then you will get cold faster.

Wetsuit Fit And Condition

A new and snug wetsuits will be of course warmer than a used rental wetsuit that is not completely the right size for you. Even the best and thickest wetsuit out there won’t keep you warm if it’s too big and water constantly flushes it.

Duration And Number Of Your Dives

The longer you stay under the colder you will feel. Also if you make more dives in one day and/or if you are diving for a few consecutive days you will feel colder.

How Quikcly Do You Feel Cold?

Some people are cold all the time while others are hot and can stand cold without problems. This depends somewhat on where you live and on your personal aversion to cold. Also – women tend to get colder quicker than men. You probably know if you easily get cold or not.

diver-diving-in-a-wetsuit

Diving.

Choosing Diving Wetsuit Thickness

Now – after all that it may seem like a good idea to simply buy the thickest suit possible. You’d rather be warm than cold, and you can always let some water into your suit if you get overheated. However, a thick suit is clumsy and harder to move in because the thicker neoprene provides more resistance to your limbs. If you plan on a very active dive, you’ll want to test your wetsuit to make sure that movement in it won’t tire you out too quickly.

Fortunately, wetsuits also vary in coverage, which gives you some flexibility in building the perfect wetsuit combination for your dive. Wetsuit coverage starts from a shorty, which has short sleeves and short legs and covers about as much of your body as a T-shirt and a pair of shorts.

From this, wetsuits provide more and more coverage, up to full body suits with booties, gloves and hoods. However, this full getup greatly reduces your movement. In the same vein as not choosing a suit that is too thick for your dive site’s water temperature, don’t trust manufacturers or stores that claim you will be comfortable with the thinnest model available. At the end of the day, most wetsuits are made of neoprene, and they will not vary too much in warming abilities. If you want to choose a design that is thinner than what is recommended, opt for some layering pieces in case you need to supplement your wetsuit. It’s not just uncomfortable to be too cold while on a dive, but it’s also dangerous. There’s nothing worse than having to turn back or cut off a dive early because you’re too cold.

Warm Water Wetsuits

For wetsuits, warm water describes a temperature range between 78 and 85 degrees (25-30C). Warm water wetsuits are best for diving in Mediterranean locations, locations in Oceania, waters off of Hawaii and various other locations. Typically, a wetsuit for warm water will be in between one-half millimeters thick and three millimeters thick, which is about an eighth of an inch thick.

If you’re planning on diving deeper or longer, add a second layer. Often, a shorty or tunic of three millimeters combined with a thin jumpsuit will keep you warmer but still allow for you to make adjustments for warmer or cooler conditions.

Temperate Water Diving

Temperate water is between 60 and 75 degrees (15-24C). This range usually applies to dive sites on the Pacific Ocean side of Mexico, the Red Sea and the Southern Great Barrier Reef. Wetsuits designed for temperate water are usually between four and six millimeters thick, or three-sixteenths of an inch thick. A spring suit or a full suit will be enough for this temperature range, but if you are especially sensitive to cold, or if you will be diving to greater depths, you’ll probably want to add another layer. You can use a hood, a vest or a tunic between three and five millimeters thick to provide the extra protection you’ll need.

Wetsuits For Cold Water Diving

Cold water dive sites are spread out all along the West Coast of the United States, from parts of California to Oregon and Washington. New York and other New England states also have cold water dive sites, and the Great Lakes are a great freshwater location for cold water dives. Northern Europe is also home to cold water dive locations. This water is between 45 and 60 degrees (7-15C). Your wetsuit should be six-and-a-half to seven millimeters thick, or one-fourth of an inch.

At this range of temperatures, the cold can become dangerous instead of merely annoying or uncomfortable. It is imperative that you not only have a wetsuit with adequate thickness, but that you also bring additional protection from the cold. To protect your extremities, you should also have booties and gloves, which need to be between five and seven millimeters. It’s also a good idea to bring a vest, a tunic and a hood, also five to seven millimeters thick, for deeper water or colder conditions.

At these colder temperatures, it is not a bad idea to consider a dry or semi-dry suit. A wetsuit will not seal against your body. This allows water into the suit, but the suit’s insulation will warm up that water and keep you warm. A semi-dry or dry suit will seal all of the water out of the suit, keeping you warmer and protecting you more. It should also be noted that amateur divers should not attempt cold water dives until they gain more experience.

Dry Suits

There is a large difference between a wetsuit and a dry suit. Dry suits are much more expensive than regular wet suits because they have special seams and finishes that will seal water out. The purpose of drysuits is to keep you dry. Not to keep you warm. Most of them have no insulation whatsoever. But as they are completely dry you can wear regular clothes under them. Usually divers using drysuits wear things like Polar Fleece under their suits to keep warm. But again – only consider a dry suit if you are going to dive in cold water areas extensively. Cold water diving is not for beginners so when you will have enough experience you will already know if you need a drysuit or not.

Choosing The Right Wetsuit

As wetsuits get thicker, they will be more expensive. Do not let this sway you from choosing the correct suit thickness. It can be hard to get over sticker shock, which is why it is incredibly important to know that you are looking at wetsuits in the correct range of thickness. If you’re not certain about the climate of your intended dive site, then refer to the areas listed with each temperature range and try to find your dive location. Unless you are diving during the winter, these general guides will give you a good enough idea of the temperature. Buying a wetsuit is an investment, so don’t take it lightly. If you’ve already been diving with rented suits, you should already have a pretty good idea of which brands you like, which thickness levels are most comfortable for you, and which levels of coverage work best for your needs.

Wetsuit Thickness Water Temperature Chart For Diving

This chart does not include factors mentioned above like number of dives etc… so adjust it to better suit your diving. Also – there is a debate going on how much heat do you actually loose through your head. Some say up to 40%, some say head heat loss is usually less than one-third to one-fifth of total heat loss. But whichever is true, head heat loss is disproportionate to other parts of your body so wearing a hood is a good idea as soon as the water starts to get colder.

Water temperature / Thickness recommended
75-85F / 24-30C  1/16″ (1.6mm) neoprene with Lycra/Polartec or 1/8″ (3mm) neoprene
65-75F / 18-24C  3/16″ (5mm) neoprene
50-70F / 10-20C  1/4″ (6.5mm) neoprene, hood, boots, also gloves if needed
35-50F / 2-10C    3/8″ (9.5mm) neoprene, thick hood, boots, gloves (7mm) or dry suit

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