Each diver has a different tolerance for water temperature, so there is no specific temperature that is too low for scuba. It’s more important to pay attention to diver condition than actual numbers and stop the session at the first sign of hypothermia.
Keep reading as we explore how temperature affects scuba diving and how you can watch out for hypothermia. We’ll also explain how to prepare for cold water diving and how you can keep warm in colder water.
How Cold is Too Cold for Scuba Diving
Cold water diving refers to dives that take place in water below 15.56° (60°F). This is when divers need to focus on increasing their exposure protection to defend against hypothermia. The water gets much cooler the deeper you go, and some polar dives start in the negatives.
Temperature may affect your preparation for a dive, but it’s not a clear indicator of whether you should continue or not. It’s better to pay attention to your own limits and how cold it can get before you’re putting your health at risk.
Hypothermia is the main concern relating to scuba diving and temperature, and learning how harmful it can be and what to look out for is essential before remotely cold dives.
Hypothermia
Hypothermia refers to a drop in the body’s core temperature. This can happen in both polar and warm waters if you are ill-prepared for the dive, including your body condition or exposure suit.
The stages of hypothermia relate to body temperature. The typical adult core temperature sits at 37°C (98.6°F), and this is when you’ll have optimal control of brain and body function.
- Temp < 35°C (95°F): Your body function starts to wane. To keep your body warm, blood shifts more to the core. This is where you start to see symptoms such as shivering, loss of coordination, dizziness, nausea, and hunger.
- Temp < 30°C (86°F): You’ll stop shivering at this point but may not have the cognitive function to recognize that you are still in danger. Pupils usually dilate at this point.
- Temp < 27.8°C (82°F): Your muscles go rigid and you’re at risk of serious cardiac complications. As your temperature drops, your symptoms will only get worse.
Because cognitive function drops after the initial onset of hypothermia, it’s suggested to stop a dive at the first physical sign: shivering.
A properly insulated body should be able to tolerate the water without shivering, and this is a quick and easy way to recognize the hazardous condition with little discretion.
Can You Go Scuba Diving in Winter?
You can go scuba diving in winter, but the effects vary depending on where you want to dive.
For example, a Lake Huron dive in September may occur at 20°C (68°F), while the same dive in January averages 0°C (31°F). A dive in the North Florida Springs holds at 21°C (72°F) year round..
You should pay more attention to location, then determine whether you are prepared to dive in the average temperature in that location during winter. Make sure you’re well-conditioned and have the proper equipment for your dive, especially if you’re diving in extremely low temperatures.
How do Divers Dive in Cold Water?
Diver’s focus on preparation and proper gear when diving in cold water.
Preparing to Dive in Cold Water
It’s even more important to be well conditioned to diving when you’re working in lower temperatures. This means you should have a good baseline of fitness, but you should also focus on strengthening your mental strength.
Because hypothermia is an added concern, you need to know how to keep a level head and recognize symptoms in yourself and others.
Divers understand that there are buoyancy differences when working in cold water. This comes from the increased exposure suit and differing weight requirements. Learning how to dive in a drysuit and using different or additional gear is essential
If divers plan on visiting deep wrecks or caverns more common in cold water environments, they may need additional certifications or training.
A well-prepared diver will add heat sources to the boat and have hot/warm water available for warm drinks and to pour into wetsuits (if using wetsuits) between dives.
Different Gear in Cold Water
Part of the preparation is understanding the different gear you should have when diving in cold water.
A wetsuit works best in warmer temps, but you may be able to get away with a 5mm or 7mm double layer wetsuit in colder water. This depends mostly on personal preference, but understand that drysuits allow for greater insulation in colder water.
Drysuits involve thicker material and do not fit to the skin like wetsuits do. Instead of allowing a thin layer of water for insulation, drysuits have more room for insulating undergarments that can draw moisture from the skin and allow it to breathe.
Most divers opt for merino wool undergarments for breathability and warmth. You can also add on accessories such as:
- Hoods
- Vests
- Gloves
- Neoprene socks
Some scuba regulators work poorly in colder temperatures, and divers opt for specific cold water designs. These include features that prevent freezing, including:
- Environmental seal
- Metal second stage
- Heat sink
- Diaphragm model first stage
These features better insulate the regulator to keep it performing well in lower temperatures.
How Cold Can You Dive in a Drysuit?
You can use a drysuit in any temperature, but the lowest cold setting depends on your personal capabilities and what you have underneath your drysuit.
These suits are not waterproof or warm on their own. Instead, drysuits focus on keeping out all water so your body and undergarments remain dry while using it. Using insulating undergarments is implied, and there will be a big difference depending on what you wear.
What is the Difference Between Warm Water and Cold Water Diving?
There are a few key differences in warm water and cold water diving. As we’ve already explored how an exposure suit for cold water diving is set up, we’ll focus on what is more likely in each setting and how to set your expectations correctly.
Divers are more buoyant in cold water due to the use of a thicker suit. You can offset this by filling your drysuit with air, choosing a steel tank over aluminum, or wearing donut wing BCDs. You should usually carry more weight in cold water than you would in warm water.
Cold water dive sites are less visited, and you can witness untouched landscapes like kelp forests and sunken ships.
Warm water is more prone to marine animals like dolphins, stingrays, sea turtles, and manta rays. A cold water diver can show you Pacific Octopus, sea lions, sea dragons, and arctic seals. The marine life also depends on the specific location of your dive.
A cold water dive should also focus on staying warm before and after the dive, requiring additional preparation and consideration. Understanding how your body responds to changes in temperature can prevent you from doing something unintelligent (like hopping into a hot shower right after your dive).
How do Scuba Divers Stay Warm?
There are a few ways scuba divers stay warm apart from wearing proper gear.
If you’re wearing a wetsuit, you can replace the insulating layer of water with warm water as it cools.
Focusing on keeping the body hydrated before, during, and after the dive also helps you maintain proper core temperature. By avoiding caffeine and eating healthy and balanced meals, you can keep energy consistent and avoid exhaustion (especially with multi-day dives).
Drying off in between dives keeps you warm after and in between, and microfiber towels help remove cold water quickly.. Allowing your exposure suit to dry completely between dives is important for proper insulation, although this matters more with wetsuits that aren’t wholly waterproof.
Staying warm may be a task, but it’s an important part of keeping your cold water dive safe and enjoyable.
References
https://www.girlsthatscuba.com/staying-warm-scuba-diving/
https://dive.site/blog/wetsuit-vs-drysuit/
https://pros-blog.padi.com/how-cold-is-too-cold-2/