What Should the Temperature Be in a Hot Tub?

I love being able to soak in our hot tub with my wife and kids. But between our age differences and preferences, I’ve wondered what should the temperature be in a hot tub?

Here’s what I’ve learned over the course of owning 4 hot tubs:

Hot tub temperatures are a matter of personal preference. But the maximum safe temperature is 104° F (40°C). Many prefer temperatures between 100-102° F (37.7°C to 38.8°C). However, medical conditions, prescription drug use, alcohol and the age of the users can all affect suggested hot tub temperatures.

However, there’s a lot more to know about hot tubs, water temperature, safety, and enjoyment.

So in this article, we’re breaking it down and examining everything there is to know. So if you’ve wondered what should the temperature be in a hot tub, let’s explore!

Confused about hot tub chemicals and not sure which ones are the best?

I take the mystery out of it in a recent article. I explore not only which chemicals you need, but also which ones you don’t that can be a waste of money. But I also explore which chemicals are best for sensitive skin and how to avoid the dreaded hot tub rash.

So just click the link to read that now on my site.

What temperature should a hot tub be set at?

Of course, to a degree (pun intended), it comes down to personal preference.

  • Do you want a quick soak with your wife after the kids are asleep?
  • Do your elementary age kids use it often
  • Is it super hot or super cool where you live
  • Does anyone who uses the tub have any medical conditions

Those are all questions to ask yourself first before setting the temperature of your hot tub.

I have 3 kids, two tweens and 1 toddler. Outside of the summer months, the whole family likes to get in. So, I have ours set to 98°.

That temperature is safe for the kids, enjoyable for my wife and me, and we can soak a little longer before needing to get out.

But others prefer a temperature up to 104°. The most common temperature for a hot tub to be set to is between 100-102° F (37.7°C to 38.8°C).

Just remember that the higher the temperature, the shorter the time you should soak in it.

Here’s a handy chart showing temperatures and how long you should soak in your hot tub.

Hot Tub Temperature Max Soak Time
98° F (36.6°C) 30 Minutes
99° F (37.2°C) 28 Minutes
100° F (37.7°C) 25 Minutes
102° F (38.8°C) 20 Minutes
104° F (40°C) 15 minutes

Just remember that this is a guide.

Health conditions, outside temperatures, direct sunlight, and alcohol or prescription drug use can affect soak times considerably. Always be safe and never use yours alone and when in doubt, get out.

Individuals with a history of health issues or who are on prescription medication should ask their doctor.

What is the maximum safe temperature for a hot tub?

Most hot tubs come set from the factory to 100° F (37.7°C). But some prefer a higher temp, up to 104° F (40°C). 104° is generally considered the maximum safe temperature for a hot tub.

The US Consumer Products Safety Commission says this regarding the maximum temperature for a hot tub, from their 1979 advisory:

“Hot tub water temperatures should never exceed 104 degrees Fahrenheit. A temperature of 100 degrees is considered safe for a healthy adult.”

They go on to add the following precautions:

  • Pregnant women – soaking in water above 102 degrees Fahrenheit can cause fetal damage during the first three months of pregnancy
  • People taking medication which causes drowsiness should not use hot tubs
  • If you have a history of heart disease, diabetes, or blood pressure issues, consult a doctor first

Ultimately, with 3 kids, one of whom is a toddler, I prefer to keep our hot tub set around 98°.

Remember too that a hot tub can make you dehydrated. I cover everything you need to know about hot tubs and dehydration in a recent article.

What really surprised me was how quickly the symptoms of dehydration can set in when using a hot tub (especially if we’ve been drinking alcohol or haven’t had enough water.

Just click the link to read it now on my site.

What temperature is too cold for a hot tub?

This question could mean 2 different things, so I’m going to answer both.

First, and most likely, you might want to know what outside temperature is too cold to use a hot tub in. Personally, I love using a hot tub when it’s cold outside. I’ve sat in a hot tub once in Lake Tahoe surrounded by snow and it was glorious.

Granted it’s chilly getting from the hot tub back to the house.

There isn’t a hard and fast rule about outside air temps and hot tub usage. But there are some good things to be aware of, such as:

  • Don’t be tempted to turn the hot tub temp up above 104°, that’s still unsafe even in cold weather
  • Do limit your hot tub soak to about 15 minutes as the hot water can fool you into not realizing an overall body temperature drop
  • Do run the jets and waterfalls to help keep the water in those pipes from freezing

It’s also a good idea to wear a ski cap or other hat as we lose a lot of body heat through the top of our head and that’s the body part that is least exposed to the hot tub’s warm water. Water shoes can also help your feet and to avoid slipping as you head quickly back to the house.

As for the water temperature itself being too cold, as long as you have power to the tub and are maintaining proper water chemistry, you can set your hot tub temperature as low as you like.

Just understand that it’s not a pool, and will still be warm no matter how low you bump the temp. In most cases, 80° is the lowest setting on hot tub control panels. But unless it’s wintertime for you, the actual water temps may not get that low.

What is a good temperature for a hot tub in the summer?

Well, unless your hot tub is indoors or you live in an especially cool climate, just remember that the sun’s summer heat will naturally heat your hot tub beyond what you have the temperature set to.

When our summer started here in Texas, despite having our temperature set to 98°, the actual water temperature, quickly jumped to 104° (and higher as it got hotter outside).

With the outside temperatures getting close to 100°, that’s just not enjoyable!

At first, I tried just lowering the temp on the hot tub’s thermostat, but that didn’t really do much. What finally worked was to read the manual (something a lot of us guys avoid doing at all costs).

Now, we have a Master Spa Twilight hot tub, so yours could be different.

I ended up setting ours to what they call “sleep mode” which only turns on the heater during filter cycles. The end result is that the consistent water temperature can be as much as 20°F/10°C lower than the temperature you have it set at.

I still have mine set around 92° (it’s almost fall here in Texas, but we’re still seeing highs in the high 90’s). The actual water temp now is 99° which, when not in the full heat of the day, feels great in the mornings and early evenings.

What happens if a hot tub is too hot?

As I mentioned above, you should never get in a hot tub that’s above 104° F (40°C). It’s just not safe.

It’s also a great idea to get a small floating thermostat to measure the water temperature as you can’t always rely on the digital readouts on your control panel. ‘

In many cases, manufacturers use a temperature probe pressed up against the outside shell of the hot tub to measure that temperature. So aside from having to try and read the temp through the thick acrylic shell, I’ve also seen them come loose and just be sitting there surrounded by that spray-on foam.

Newer ones may measure the temp at the heater, but it’s still now always accurate.

So get a small thermometer that can actually just float in the water; it’s a fast and easy way to check the temperature accurately.

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How do I cool down my hot tub?

Unfortunately, there’s not a way to quickly cool down your hot tub.

Yes, obviously you can lower the temperature on your hot tub. But as I mentioned above, if it’s summer and you live somewhere hot as I do, that will only get you so far.

Don’t think about adding ice to your hot tub.

Unless you own a restaurant-style ice machine, you won’t be able to add enough to make much of a difference. What could help would be to add more water from your hose.

City water temps are typically somewhere around 65℉ and well water even lower. So aside from the bit of water sitting in your hose, water from a hose will be much cooler than the water in your hot tub.

You may find in order to not overfill that you have to drain off some of the water first.

So find where your drain is (which often requires removing a panel) and drain off about 25% of the water. Once drained and the valve is closed, then add new water from your hose.

Always check and treat the water once you’re done refilling, before getting into the hot tub.

And since we’re talking about adding water to your hot tub, it’s always recommended to change the water completely in your hot tub every 3-5 months depending on how often you use it.

I cover everything you need to know about how to do that quickly and easily in a recent article, including how you can actually drain your hot tub in under 15 minutes!

Just click the link to read it on my site.

Does a hot tub heat faster with jets on?

No is the short answer.

But, it’s important to understand the components of a hot tub to answer this question fully. You have:

  • The heater – A long silver tube, often attached to the control box. Water passes through and the heating element inside raises the water temperature
  • A pump – This is what pushes the water through the heating tube, sucking water from the pipes that connect to the hot tub. While not the same as a blower, this does create motion in the water
  • The blower – This is not connected to the pump or the heater and doesn’t have water passing through it. This is more like a vacuum cleaner which pushes air instead of sucking air. This is what creates the vigorous bubbles in the hot tub when it’s turned on

Because the jets are aerating the water, they actually cause the temperature to drop a little. So avoid turning them on whatsoever if you’re trying to raise the water temperature.

Also, keep your hot tub cover on while trying to raise the water temperature. That will cause temperatures to go up a little bit faster.

Can I keep my hot tub cool in the summer?

The short answer is you can try.

As I got into above, when the outside temperatures are close to 100°, it will be very hard to keep your hot tub cool like a swimming pool.

Don’t be tempted to just cut the power to the hot tub. That can cause the water to stagnate in the lines and could lead to bacteria or viruses growing. Even if you’re still treating the water, with no way to circulate it, it’s still a dangerous thing to do.

You can, however, do what I did and switch the mode of the heater.

My hot tub (Master Series Twilight) has 3 modes:

  • Standard Mode – Just set the control to the desired temp. is programmed to maintain the desired temperature. The temp displayed is based on the last read temp after the pump has been going at least 2 minutes
  • Economy Mode – Only kicks on the heater during the filter cycles (often 2x/day). Temps can fluctuate outside of those times
  • Sleep Mode – Heats the spa to within 20°F/10°C of whatever you have the temp set to. In summer the difference will be minor

I switched our hot tub to “sleep mode” and it dropped the temp from 106° down to 99° in the middle of summer (it gets hot here in Texas), taking it from unuseable to enjoyable. It took about 2 days before I noticed the drop after switching.

Did I cover everything you wanted to know about what the temperature should be in a hot tub?

In this article, we took a look at hot tub water temperature.

We looked at the maximum safe temperature, as well as typical temperature preferences. But we also looked at how to get your hot tub cooler in summertime and how to cool down a hot tub that’s gotten too hot.

What’s your favorite temperature on your hot tub?


Photos which require attribution:

109/365 19 April 201920190419_173833-01 by easegill is licensed under CC2.0

Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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