Why Are Swimming Pools Always Cold

Swimming pools always seem to feel cold, whether they’re outdoor or indoor pools. This sensation has something to do with how our bodies perceive temperature, but it also has to do with swimming pools being often kept cool on purpose.

Swimming pools are always so cold because the water captures heat so effectively from our skin and because water is slow to heat up in the sunlight. Also, lap pools need to be cold for exercise purposes. But in no case should you swim in dangerously cold waters, below 70°F (21.11°C).

This article will detail why swimming pools are always so cold, advise on proper pool temperatures, and gives tips on knowing if pool water is too cold or too hot.

cold after swimming

Three Reasons Why Swimming Pools Feel Cold

There are several good reasons why swimming pools usually feel as cold as they do, including how water removes heat from our bodies better than air does, that lap pools are kept cool on purpose, and that outdoor pools are slow to heat up. 

Some of these reasons also have to do with our perception of cold. 

Water Conducts Heat Better Than Air

One major reason why swimming pools are cold is that they conduct heat better than the air. Basically, you feel colder in the water because water does better than air at transferring heat away from your skin.

When it’s hot outside, you feel hotter than the air temperature because your skin warms and then stores heat, and the air does a poor job capturing and circulating the heat from your skin. That’s why you sweat. That ensures the heat has a way to leave your skin via evaporation of moisture. 

Still, dunking yourself in a pool is a much more efficient way to draw heat from your skin. Even water with the same temperature as the air outside will feel cooler than the air does.

Lap Pools Are Kept Cool for Exercise

Lap pools are kept cool on purpose so that they’re more comfortable and safe for exercising in. Typically, temperatures are between 78-86°F (25.56-30°C) in recreational pools but even cooler for lap pools for competitive swimming. 

Competition swimming pools are generally kept at a temperature between 77 and 82°F (25 and 27.78°C), ensuring that athletes perform their best without worrying about dizziness. 

Lower temperatures allow for a higher heart rate and heavy breathing without negative effects like overheating or blood pressure changes.

Outdoor Pools Are Slow To Warm Up

Water takes a lot of energy to heat up or cool down; it’s quite resistant to temperature changes. This resistance to temperature changes means that outdoor pools will be slow to match the outdoor air temperature, even in summer.

If you want your swimming pool to heat up quicker and stay warm for more of the year, you can try the Intex Solar Pool Cover. This cover captures sunlight and warmth to heat your pool while keeping out debris.

What Happens When You Swim in Too Cold Water?

When you swim in too cold water your body will start circulating more blood. However, after some time, your body will begin to restrict that blood flow, which is potentially fatal. Even water at 50°F (10°C) is deadly, and water between 60°F and 70°F (15.56°C and 21.11°C) is even more dangerous. 

This danger exists because water draws heat away from your body quickly and effectively and because your body responds to the sudden change in temperatures by changing blood pressure.

When it’s cold, your body will widen its blood vessels to allow more warm blood to circulate through your body. This is a good way to adapt to cold temperatures temporarily, but your body won’t maintain this state for very long.

When it’s very cold or when you’ve been exposed to the cold for a long time, your body will start restricting the flow of blood to your extremities by closing off those blood vessels to protect your core body temperature. 

Your body can only do this for so long until it’s forced to send cold blood to your organs, risking hypothermia.

See the following chart of common symptoms at various water temperatures:



77°F (25°C)

Breathing becomes more difficult.

60–70°F (15.56–21.11°C)

You begin hyperventilating, unable to control your breath.

50–60°F (10–15.56°C)

Water temperatures are immediately life-threatening. You begin going into cold shock and start gasping.

40°F (4.44°C) and below

You become completely unable to control your breathing, and the water feels painful like it’s burning.

Things That Influence Your Ability To Swim in Cold Water

Various factors influence how severely your body will react to cool or cold water, including: 

  • Acclimation to the cold.
  • Body fat percentage.

The more your body is adapted to cold temperatures and acclimated to cold water swims, the better it will circulate blood efficiently and reduce the risk of cold shock.

Like seals, whales, and other animals with blubber, having more fat will better insulate you from the cold. Although you’ll still experience cold shock, you’ll be incapacitated more slowly and have a lower risk of hypothermia.

However, even the most acclimated swimmers with body fat should be careful about swimming in cold temperatures, as the effects can still quickly become life-threatening. 

Watch for shivering, a sign that the water is cold enough to give you hypothermia.

How To Prepare for Cold Water Swimming

To keep yourself warm enough while swimming in cold water, you can try wearing a swim cap and earplugs, plus a wetsuit such as the OMGear Wetsuit. This suit is made from 90% neoprene and 10% nylon, so it’ll keep you warm but still retains some amount of stretch for comfort.

Wetsuits are more effective at keeping you warm the thicker they are and the more they cover your body. Make sure to research the water you’ll be swimming in ahead of time and buy a suit with the appropriate level of thickness and the right cut for your needs.

Another option you have is to purchase swimming socks, gloves, or boots. These are ideal for cold waters, like in an open water swimming competition or scuba diving.

What Happens When You Swim in Too Hot Water?

When you swim in too hot water you may experience a swift decrease in blood pressure. This includes hot tubs that are kept above 104°F (40°C). Such high temperatures are dangerous because it can cause you to lose consciousness, which may lead to drowning. 

More health problems brought on by swimming in water that’s too warm are as follows:

  • Nausea
  • Vomiting
  • Light-headedness
  • Heart arrhythmia
  • Lung failure
  • Dehydration
  • Electrolyte imbalance
  • Muscle spasms

You shouldn’t exercise in a hot tub for more than 15 minutes maximum. If you feel dizzy while you’re swimming, make sure that you get out of the water and rest. 

You may also run into this issue when you swim more strenuously in recreational pools that are kept too warm. 

Normally, recreational pools are kept between 78°F to 86°F (25.56°C to 30°C), which is safe for swimming, but if this isn’t maintained well, it can cause serious health problems for swimmers, even heart damage.

For competitions in the open water, the water temperature is typically tested to make sure it’s no greater than 87.5°F (30.83°C); additionally, if the race is 5 kilometers (3.11 mi) or longer, the temperature must be 85°F (29.44°C) or lower.

How To Cope While Swimming in Warm or Hot Water

You can do several things to make your swim in warm or hot water safer and more tolerable. 

These methods include:

  • Add and extend rest periods, add 10–20 seconds more between sets than you otherwise would, and take rests more frequently.
  • Decrease the distance you’re swimming in each rep, even if it takes you longer to complete the full distance.
  • Do shorter drills focused more on building technique than building endurance; this is a good way to make the most of a hot pool.
  • Stay hydrated before, during, and after your swim, even more than you would when rehydrating on land.
  • Try dryland training techniques for swimmers, like push-ups and jump squats.

Remember that you’re better off being safe while exercising than overexerting yourself and potentially causing damage.

Try Aquatic Therapy

Aquatic therapy relies on warm water for guided, gentle in-water exercises to restore the body’s health. 

This therapy is one case where it’s appropriate to use warmer water because the exercises involved aren’t strenuous and don’t involve the same increase in heart rate that you get during lap swimming.


Swimming pools feel cold because the water does a good job removing heat from our skin and because lap pools must be cool to facilitate safe exercise. 

Outdoor pools feel cold because it takes so much energy from the sun to heat a large body of water like a pool. Generally, you want your swimming water to be between 77°F and 86°F (25°C and 30°C).


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