What’s The Ideal Swimming Pool Temperature?


Unless you’re a penguin or a polar bear, jumping into an ice cold pool probably isn’t your idea of summer fun.

But then again, when it’s a hundred and eighty-seven degrees outside, no one wants to swim in a giant hot tub either.

So, yeah, the comfort of your swimming pool is an issue, but that’s not the only reason temperature is important.

Why pool temperature is important


The temperature of the pool also adversely affects your pool’s chemistry levels.

And ugh, how many times do you want to balance your pH levels in a day?

The thing is that bacteria and algae LOVE warm water.

The warmer, the better.

So, when your pool water gets too warm—say over 85°F—algae spores and bacteria find a cozy corner of your pool to snuggle up in and start a family.

And those things affect your pool chemistry because your chlorine depletes itself trying to fight it off and your pH levels get all out of whack. 

And then you have the effects of pool temperature on the swimmers.

While competitors might want cooler temperatures, elderly people and small children might need warmer ones.

But we will get more into that later.

What’s the ideal pool temperature?

Everybody is a little bit different and might prefer their pools cooler or warmer for various reasons.

But for the average swimmer, most experts agree that 77-82° is just about perfect for everyone.

It’s low enough to keep bacteria from nesting and high enough to take the chill off.

When you want a warmer temperature

A pool should never be above 95°, but a warmer pool temp might be preferable for certain people.

Older people or people with arthritis, for example, sometimes find that water temperatures between 90-92° helps to reduce joint pain.

Warmer water stimulates blood flow and loosens up muscles, making movement under water much more bearable.

Water aerobics instructors usually opt for these warmer temperatures to ease joints and muscles into the workout. 

According to the US Water Fitness Association, warmer water temps (84-90°) are also best for beginning swimmers taking lessons.

It helps to keep them comfortable and relaxed for learning a new activity.

They break the temperatures up according to age groups, but keeping your water somewhere in this range is probably pretty comfortable for most people. 

When you want a cooler temperature

There has been a lot of hype on cold water swimming and there are some health benefits associated with it.

But it’s important to know the risks and only use extreme temps under a doctor’s supervision. 

How cold is too cold?

According to the National Center for Cold Water Safety, temperatures below 50°F are low enough to cause total loss of breathing control, shock and death.

Below 40°F is so painful that it feels like your skin is on fire. 

But even temps below 77°F starts to affect breathing. 

The only time cooler water temperatures (below 77°) might be appropriate are when someone is training for competition and are being closely monitored by a professional.

The reason cooler water is better for competitive swim training is because warm water can cause the swimmer to become overheated and dehydrated.

How to measure pool temperature

There are several ways to measure your pool’s water temperature.

If you have a swimming pool heater, it probably has a thermostat built in that gives you a constant reading.

But most people also use a pool thermometer so that they can compare the two and make sure they are getting the most accurate reading. 

There are a couple of different options to choose from in pool thermometers.

  • Digital floating thermometer. Has a display on the unit or a wireless display you can put in another location.
  • Analog floating thermometer. Gives you a reading with a mercury line.
  • Infrared thermometer. Measures water temperature whenever you point the device at it.

How to control pool temperature

Unless you live in an extremely warm climate, you’ll need some type of pool heater to keep your water temps at safe swimming levels.

And the great thing about this is that most of them have built-in thermostats so that they run when they need to heat the water and shut off automatically once the water reaches a certain temperature. 

However, if you don’t want your heater running day and night, there are things you can do to prevent heat loss.

Heat loss occurs naturally overnight when the cool air hits the water. To prevent some of that and save on energy costs, you should be using a pool cover any time the pool is not in use.

And to go the extra mile, make sure it is a solar cover.

A solar cover will also help to convert some of the heat from the sun into heat for your pool, taking some of the burden off your pool heater.

To keep your pool temp regulated, you’ll need to make sure that you stay on top of repairs and maintenance to keep your heater working its best.

This is why using a thermometer is important. If you’re noticing that your water temperature is not where it should be or that your heater is working overtime with little effect, you will know it’s time to check your equipment.

Heating costs & efficiency

According to ENERGY.GOV, “The energy consumption for each degree rise in temperature will cost 10%-30% more in energy costs.”

The reason for this is that it is running longer to keep the temp higher.

But if you’re using an inefficient or old pool heater that is not longer running optimally, your costs could be much higher. 

Bottom line

There are definitely a few factors to consider when deciding on an optimum pool temperature for your pool.

But as long as you stay within the 77-82° range, you can choose the temp that feels good to you.

If energy cost is your main concern, though, you might start on the lower end of that range and test it out for a couple of days.

But if other issues such as arthritis or relaxation are your main concerns, start on the higher end and lower it if you need to.

The bottom line is that you always keep safety in mind first and foremost and test the water, especially before allowing children or elderly to swim.

As long as you’re not giving anyone frostbite, you’re not likely to hear many complaints!

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