Best Pool Thermometers
The best pool thermometer for most people is the GAME 14000-BB Digital Pool and Spa Thermometer, because a big LCD reading is far easier to trust than squinting at a tiny painted scale, and it floats or tethers wherever you want it. The decision that actually matters is digital versus analog: a digital thermometer gives you an exact number on a screen but runs on a battery or a small solar cell, while an analog float has no battery to die and costs a few dollars, but you read the temperature off a small tube and it is only good to a couple of degrees. Either kind is accurate enough to run a pool. You want a thermometer at all because water temperature drives two things you care about: comfort, since most swimmers are happy between 78 and 82 degrees Fahrenheit, and chemistry, because chlorine burns off faster in warm water and algae takes hold quickly above about 85 degrees, which is exactly when you need to watch your chlorine level. Here are the picks, sorted by how you want to read the temperature.
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GAME 14000-BB Digital Pool and Spa Thermometer
Who it is for: Anyone who wants an exact temperature they can read at a glance from the deck without doing math on a painted scale.
- +The large LCD shows the water temperature as a plain number in Fahrenheit or Celsius, so there is no guessing between the marks the way there is on an analog tube.
- +It floats upright on its own and comes with a tether so you can tie it to a ladder or the skimmer and keep it from drifting to the far end of the pool.
- +It works in a pool or a hot tub, and the digital sensor settles on a reading quickly instead of slowly creeping like liquid in a tube.
Watch out: It runs on a battery, so it will eventually go dark and need a replacement; a dead reading is the tradeoff for the easy number. Pull it out before you shock the pool or run it through a hard freeze.
Poolmaster Premier Floating Pool and Spa Thermometer
Who it is for: People who want something cheap and reliable that never needs a battery and does not mind reading within a degree or two.
- +There is no battery and no electronics to fail, so it just works season after season, which is the whole point of a simple float.
- +The shatter-resistant casing shrugs off being knocked against the deck or the pool wall, unlike the old glass tube thermometers that cracked if you looked at them wrong.
- +It comes with a cord so you can tie it off, and the scale is large enough to read from a few feet away without leaning over the water.
Watch out: You are reading a liquid or dial scale, so you get the temperature to about a degree or two, not an exact decimal. If you need a precise number for a heater or spa, buy the digital pick.
Inkbird IBS-P02R Wireless Floating Pool Thermometer
Who it is for: Heater and spa owners who want to check the temperature from inside the house or the deck without walking to the water.
- +A floating waterproof sensor sends the reading to a separate display unit, so you see the pool temperature without going outside, which is handy when you are deciding whether to fire up the heater.
- +It logs and shows the current temperature continuously, so you can watch a heated pool climb to your target instead of checking it by hand every twenty minutes.
- +The floating transmitter is built to sit in chlorinated water full time, and the display runs indoors on its own power.
Watch out: It is more to buy and set up than a plain float, and radio range is limited, so a far-off pool or thick walls can drop the signal. The Govee WiFi Pool Thermometer is a similar option if you would rather read it in a phone app.
Aquatix Pro Floating Pool Thermometer
Who it is for: Anyone who just wants a rough water temperature for a few dollars and does not care about a screen.
- +It is about as cheap as a pool thermometer gets while still being shatter-resistant and coming with a string to tie it off.
- +It floats and reads fine for the one job most owners need, which is knowing whether the water is warm enough to swim and roughly where it sits for chemistry.
- +Losing or replacing a cheap float stings a lot less than replacing a smart unit, and it is easy to keep a spare on hand.
Watch out: The scale is small and the accuracy is only to a couple of degrees, so it is a rough gauge, not a precise instrument. Tie it off, because an untethered float is the pool thermometer most likely to vanish under a cover or over a wall.
What actually matters when buying
Digital or analog is the real decision. A digital thermometer shows the temperature as a number on a screen, which is easier to read and better if you need an exact figure for a heater or a spa, but it runs on a battery or a small solar cell that eventually needs attention. An analog float reads the temperature off a liquid or dial scale, is good to about a degree or two, costs a few dollars, and never has a dead battery. For most owners the digital reading is worth it because you actually trust the number; buy analog if you want the cheapest thing that will never leave you staring at a blank screen.
Accuracy is fine either way, so do not overpay for it. Both digital and analog pool thermometers are accurate to within roughly one to two degrees, which is all the precision a pool needs; you are not running a laboratory. Where they differ is readability, not truth. A wireless or smart thermometer is not more accurate than a two-dollar float, it just saves you the walk to the water. If a reading looks wrong, it is almost always because the thermometer is sitting in a sun-baked shallow corner or right in front of a return jet, not because it is broken.
Where you float it changes the reading. Float the thermometer in open water away from the return jets, because water coming back from a running heater reads warmer than the pool and cold fill water reads cooler. The shallow end over a dark surface on a sunny afternoon also runs a few degrees hotter than the deep end, so pick a spot that represents the bulk of the pool. A floating thermometer measures the temperature near the surface, which is what swimmers feel first; the water a few feet down is usually a little cooler, especially early in the season before the pool mixes.
Tether it and keep it out of the freeze. Tie the thermometer to a ladder rail, the skimmer, or a return fitting with its cord, because an untethered float drifts to the far wall, hides under a solar cover, or flips over a raised edge and disappears. The other thing that kills a pool thermometer is winter: a glass tube or a water-filled housing can crack when it freezes, and a battery unit does not like the cold either, so pull the thermometer out when you winterize the pool and store it dry. Rinse a smart sensor and let it dry before it goes in a drawer.
Temperature is a chemistry input, not just a comfort check. Warm water makes chlorine disappear faster and lets algae bloom, so a pool sitting above 85 degrees needs a closer eye on sanitizer than the same pool at 78. Temperature also feeds the saturation index that tells you whether your water is scaling or corrosive, which is why our saturation index calculator asks for water temperature along with pH, alkalinity, and calcium hardness. Knowing the actual number, rather than guessing, is what lets you dose correctly instead of chasing a cloudy or scaly pool. Pair the thermometer with a good reading of the rest of your water balance.
How we picked
This is a research-based guide. We compare pool thermometers on the things that change the buy, digital versus analog readout, accuracy, how easy the display is to read from the deck, durability of the housing and tether, and whether a smart model earns its extra cost, weighed against a broad set of owner reviews across the established brands. We do not bench-test thermometers in a calibrated bath, and we take no payment for placement. Every product here is a real, currently sold model, and a commission never changes a pick. A pool thermometer is a rough field instrument; treat any reading as good to a degree or two and place it away from jets and hot spots for the truest number.
Keep your water right, too
Gear handles the cleaning; chemistry is the other half. Useful next: how to heat a pool, best pool heaters, best solar pool covers, ideal pool chemistry levels, pool maintenance schedule.
Frequently asked questions
What is the best pool thermometer?
For most people the best pool thermometer is a digital floating model like the GAME 14000-BB, because a plain number on an LCD is easier to trust and read than a tiny painted scale, and it works in a pool or a hot tub. If you never want to deal with a battery, a shatter-resistant analog float from a brand like Poolmaster is cheap and reliable to within a degree or two. If you want to check the temperature from the deck or your phone without walking to the water, a wireless model like the Inkbird IBS-P02R or the Govee WiFi thermometer is the one to get. Pick by how you want to read it, because they are all accurate enough to run a pool.
Are digital and wireless pool thermometers accurate?
Yes. A decent digital or wireless pool thermometer reads within about one to two degrees Fahrenheit, which is all the accuracy a pool or spa needs, and that is the same real-world accuracy you get from a good analog float. Wireless does not make the reading more precise, it only saves you the trip to the water and lets you watch a heated pool climb to temperature. When a reading looks off, the cause is almost always placement, a thermometer baking in a sunny shallow corner or floating right in front of a warm return jet, rather than the instrument itself.
Where should I put a pool thermometer?
Float it in open water toward the middle of the pool, away from the return jets and away from the sun-baked shallow end, so it reads the temperature of the bulk of the water rather than a hot or cold pocket. Tie it off with its cord to a ladder, the skimmer, or a return fitting so it does not drift to the far wall or slip under a cover and disappear. A floating thermometer measures near the surface, which is what swimmers feel first; if you want the deep-water temperature early in the season, remember the bottom runs a few degrees cooler until the pool mixes.
What is the ideal pool temperature?
Most swimmers are comfortable between 78 and 82 degrees Fahrenheit, and that range is also easy on your chemistry and your heating bill. Warmer than about 85 degrees and chlorine burns off faster and algae takes hold more easily, so you have to watch sanitizer more closely; much below 70 and it simply feels cold for lap or recreational swimming. Competitive lap swimmers often prefer the high 70s, while small children and older swimmers usually want the low 80s. If you are trying to hit a target, see our guide on how to heat a pool and pick equipment from the best pool heaters.
Do I really need a pool thermometer?
You need one if you heat the pool, track your chemistry carefully, or have kids or older swimmers who feel a few degrees more than you do. A thermometer stops you from overheating a pool and wasting gas, and it gives you the water temperature that both your comfort and your saturation index depend on, since warmer water shifts how your pH, alkalinity, and calcium balance out and how fast chlorine disappears. If your pool is unheated and you only swim on hot days, a cheap float is plenty; you just want a rough number, not an instrument.