Water thermometer

The Deepest Review Of The 5 Best Water Thermometers For You

As a seasoned pool and hot tub owner, you understand the importance of maintaining an ideal water temperature. However, choosing the water thermometer can be overwhelming, especially with the worry of mercury-containing devices that are often non-returnable. But fret not! Join us as we present working options that will provide accurate readings and save you money by optimizing energy efficiency. 

We have already explored different ways to enhance your hot tub experience with the best hot tub accessories, from floating thermometers to bright LED lights, and comfortable booster seats. But water thermometers go beyond aesthetics to become a constant companion in your safety and water pleasure.

In this article, we delve into the world of accurate temperature control and explore the top-rated thermometers, guide you toward calibrating your water thermometer, and answer your burning questions.

Comparison Table: Top 5 Water Thermometers That Actually Work

When it comes to water thermometers, there are two primary categories: mercury thermometers and digital thermometers. Each type has its own distinct characteristics and advantages. We will delve into the details of both, discussing the pros and cons of each. Given the inherent differences between mercury and digital thermometers, evaluating them separately and comparing the top models within each category is essential.

Mercury Water Thermometers
SplashTech Floating Buoy Pool Thermometer
SplashTech Floating Buoy Pool Thermometer
Winner in the category
The most accurate readings

Amazon rating: 4.2

Why do people buy it?
- Provides the fastest measuring
- Jumbo-sized display that ensures effortless visibility
- Has a convenient cord and a floating buoy

Jump to a detailed review
Milliard Floating Pool Thermometer
Milliard Floating Pool Thermometer
Winner in the category
The cutest design

Amazon rating: 4.4

Why do people buy it?
- The quirkiest and most playful pool companion
- Submerged underwater for measurement
- Always in sight thanks to the unique design

Jump to a detailed review
Intex Pool Thermometer
Intex Pool Thermometer
Winner in the category
The most extended service life

Amazon rating: 4.3

Why do people buy it?
- The best protection against water ingress
- Durable and resistant to any damage
- Practical neutral design for any color pool

Jump to a detailed review
Digital Water Thermometers
Game Digital Pool & Spa Thermometer
Game Digital Pool & Spa Thermometer
Winner in the category
The easiest-to-read display

Amazon rating: 4.4

Why do people buy it?
- The largest numbers on a screen
- The double-sided display can be read from any angle
- Doesn't need batteries — it's solar-powered

Jump to a detailed review
Ambient Weather Wireless Floating Temperature Reader
Ambient Weather Wireless Floating Temperature Reader
Winner in the category
The best protection against overheating

Amazon rating:

Why do people buy it?
- The best protection against overheating
- Advanced wireless connectivity and remote monitoring with extra display
- Has multipurpose measurement functions — temperature alerts and the min/max temp for the last 24 hours

Jump to a detailed review

What To Look For When Choosing A Thermometer For Water

There are several crucial factors to consider when choosing a water thermometer. Whether you need to measure the temperature of your bath water, fishing spots, or hot tub, finding a reliable and accurate water thermometer is essential. Let’s glance at the factors you should consider when making your decision.

1. Type of thermometer: mercury or digital

Mercury thermometers are traditional and widely recognized for their accuracy. Electronic thermometers, however, offer convenience and ease of use. Consider your preferences and needs to determine which type is best for you.

2. Accurate and reliable readings

A thermometer that delivers reliable readings is crucial, especially for sensitive applications such as measuring hot tub water. Always check for customer reviews and ratings to see if other buyers have found it to be reliable and accurate. In our research, we explored the top water thermometers and made a comparison table that highlights their winning characteristics, allowing you to make an informed decision based on the features that matter most to you.

3. Do you need additional features?

Some thermometers offer additional features like temperature change alerts, 24-hour maximum and minimum monitoring, and temperature trending, which can enhance your experience.

Choose a water thermometer that offers intuitive control and easy maintenance. Features such as a simple interface and quick response time can significantly improve your experience and make temperature measurement a pleasure. Detailed reviews by our team, based on real customer experience, can help you clarify how convenient it is to use.

4. Multipurpose thermometers

Think about how you plan to use the thermometer. A universal thermometer is ideal if you need it for various purposes, such as checking the water in your pool, fishing, or in your hot tub. Look for one that can work in different temperatures and different water environments.

5. Think about the design

There are a lot of inconspicuous thermometers that blend in with your snow-white pool tiles, but why not add a little fun? Explore thermometers with additional features or unique designs. From whimsical shapes to bright colors, these accessories can make the water experience more enjoyable and diverse.

Detailed Review

In this section, we will provide a comprehensive overview of functional mercury and digital water thermometers that accurately measure the temperature of our water environment. We will delve into their features and benefits to help you make an informed decision on which one to purchase based on your budget, preferences and needs.

Mercury Water Thermometers For Traditional Measuring

Mercury thermometers have been used for decades due to their accuracy and reliability. They provide precise temperature readings, making them ideal for ensuring that water temperature is at the desired level.

SplashTech Floating Buoy Pool Thermometer — The Most Accurate Readings

SplashTech Floating Buoy Pool Thermometer
SplashTech Floating Buoy Pool Thermometer

Winner category: The most accurate readings


  • Delivers the quickest reading among mercury thermometers
  • A large display that guarantees easy visibility
  • Comes equipped with a handy cord and a floating buoy
  • Durable design


  • The thermometer scale may become loose from major damage
  • Limited temperature range up to 104°F

The SplashTech Floating Buoy Pool Thermometer is a versatile option for your aquatic environments, baths, and fishing. It comes with a clear and easy-to-read scale, making it easy to use wherever you need it. The large display is a standout feature of the thermometer, making it easy to read the temperature, even from a distance without glasses.

The thermometer is quite accurate and gives you an instant reading of the temperature of your pool water. Additionally, the thermometer comes with a cord and floating buoy to make it easy to use in your pool. 

While this thermometer offers satisfactory performance, it is important to note that it may not provide the same extended service life as the Intex Pool Thermometer. Additionally, the accompanying rope, while functional, may have limited durability and could deteriorate over time. Make a note, the mercury thermometer is fragile, so serious damage can cause the thermometer scale to displace and make the reading less accurate. 

Milliard Floating Pool Thermometer — The Cutest Design 

Milliard Floating Pool Thermometer
Milliard Floating Pool Thermometer

Winner in the category: The cutest design


  • The eye-catching design ensures it never gets lost
  • Always stays underwater for measurement
  • Comes with a strong string for stability
  • A fancy and fun companion for pools, hot tubs, and all your aquatic settings


  • It may be difficult to see the reading on the display
  • Can get stuck on an inaccurate reading and require calibration

The Milliard Floating Pool Thermometer is a unique and fun addition to any pool or bath. One of the features of the thermometer is a funny little man on the top that provides good visibility, allowing you to control the position of the thermometer in the water. Also, thanks to this design, the thermometer will always stay underwater and show you the correct temperature

Included is a sturdy, long rope for anchoring in your aquatic environment. Thanks to the hole in the thermometer, you can change the string to a new one over time without any problems. 

However, there are some cons to consider. Customers have reported that the glue holding the glass temperature tube can fail, making it unsuitable for high temperatures compared to another model. The thermometer may occasionally give an inaccurate reading by getting stuck on a fixed temperature. Nevertheless, you can easily calibrate it to ensure accurate readings.

Intex Pool Thermometer — The Most Extended Service Life

Winner in the category: The most extended service life


  • The most effective protection against water penetration
  • Long-lasting and impervious to harm
  • Large and easy-to-read display
  • Functional and unbiased style suitable for any pool color


  • Comes without a string, but only with a hole for it
  • May float horizontally on the water’s surface

The Intex Pool Thermometer is resistant to both water and hot temperature changes, which means that it will continue to provide accurate readings for years to come, ensuring accurate temperature readings without any risk of damage or malfunction due to water exposure.

This thermometer’s durability is another significant advantage, as it is specifically designed to be long-lasting and impervious to harm. It can withstand the rigors of pool use, including exposure to sunlight, chemicals, and constant immersion. This thermometer not only offers exceptionally accurate data but also allows us to put in one row with the SplashTech Floating Buoy Pool Thermometer, known as the most accurate in its category.

During our team research, we noted that it can float horizontally on top of the water, and customers had to hold it underwater to measure the desired temperature, unlike the Milliard Floating Pool Thermometer which floats exclusively vertically and always stays underwater. It also causes this thermometer to often fall into the pool skimmer.

Digital Water Thermometers With Accuracy And Convenience

Digital water thermometers are a must-have for any pool owner who wants to ensure their water is at the optimal temperature for swimming. These thermometers are accurate, reliable and easy to use, making them a great investment for any pool owner.

Game Digital Pool & Spa Thermometer — The Easiest-To-Read Display

Game Digital Pool & Spa Thermometer
Game Digital Pool & Spa Thermometer

Winner in the category: The easiest-to-read display


  • The biggest display, featuring jumbo-sized numbers
  • The dual-facing screen is easily legible from any angle
  • It operates without batteries, relying solely on solar energy
  • Easy-to-understand readings


  • The screen may fog up because of poor water protection
  • Can fall into the skimmer

The Game Digital Pool & Spa Thermometer boasts accurate temperature readings, which is essential for maintaining the perfect water temperature in your pool or spa. Also, it has a large double-sided display, making it convenient for pool owners to monitor the water temperature. You don’t even have to bend over to see the temperature reading. Additionally, the thermometer operates on solar power, which is eco-friendly and eliminates the need for frequent battery replacements.

While some customers have reported that this thermometer is not as well protected from moisture as our previous thermometer and the screen can fog up, it is important to note that this is not a common problem. Additionally, steps can be taken to prevent moisture from affecting the thermometer’s performance, such as storing it in a dry location when not in use.

Ambient Weather Wireless Floating Temperature Reader — The Best Hot Tub Thermometer

Ambient Weather Wireless Floating Temperature Reader
Ambient Weather Wireless Floating Temperature Reader

Winner in the category: The best protection against overheating


  • The best remote choice for your hot tubs with protection against high temperatures
  • Extra display with advanced wireless connectivity and remote monitoring capabilities
  • Has multi-functional measurement features such as temperature alerts and the min/max temperature readings for the past 24 hours
  • The temperature receiver (which can be placed in the house) picks up signals even at a long distance


  • May require frequent battery changes every three months of active use
  • Less protected from water than mercury thermometer

The Ambient Weather Wireless Floating Temperature Reader provides various information about the water temperature and stability, not only displaying the current temperature but also indicating whether the temperature is stable, rising or falling, and how quickly it changes. Customers also mention that the thermometer helps to prevent the water from overheating or cooling down too quickly. 

One of the standout features of this thermometer is its wireless communication. You can place the thermometer in the water and display the other receiver in any convenient place and get accurate temperature readings even without being near the water. The thermometer maintains a strong and reliable connection up to 100 feet (30 meters).

While it is true that a digital thermometer is not as well protected from water as a mercury thermometer like the Intex Pool Thermometer and may develop cloudiness behind the screen, it is important to note that this issue can be mitigated by taking proper care of the thermometer. For example, you can store it in a dry location when not in use, and wipe it down after each use to prevent water from accumulating.

Mercury vs. Digital Thermometer: Depends On Your Needs

Choosing the right water thermometer is essential to getting accurate temperature readings, whether you need it for hot tubs, bathtubs, swimming pools, your favorite aquarium fish, or other aquatic environments. When choosing between a mercury and a digital thermometer, it is important to understand their unique properties. Let’s look at the pros and cons of each to help you make an informed decision based on your specific needs.

Mercury vs. Digital Thermometer: Depends on Your Needs

Mercury Water Thermometer

Mercury thermometers have been a reliable choice for measuring water temperature for decades. They are known for their accuracy and are particularly suitable for applications where precise measurements are essential.


  • The highest level of accuracy
  • A long-standing reputation for reliability
  • Easy calibration process using the ice water method


  • Contains a toxic substance that can be hazardous to the environment and health
  • The relative fragility of the case
  • Has a slower response time compared to digital thermometers

📝 A mercury thermometer is versatile and can be used as a bath or fishing water thermometer.

Digital Water Thermometer

In today’s fast-paced world, digital water thermometers offer convenience and efficiency. With easy-to-use interfaces and fast response times, digital thermometers provide fast and accurate temperature readings. Digital thermometers often come with additional features, such as memory functions, temperature alerts, and remote connectivity. 


  • The most resistant to high temperatures and mechanical damage
  • Has a user-friendly interface and an easy-to-read digital display
  • Provides fast response times, showing temperature within seconds
  • Equipped with additional features such as memory functions, and Wi-Fi connectivity for remote monitoring and control


  • Deviations in accuracy compared to mercury thermometers 
  • Requires batteries that need to be replaced periodically (except for solar-powered thermometers)
  • Problems with calibration, which takes more technical knowledge or specialized equipment

📝 A digital thermometer is ideal for daily usage, such as checking the temperature of hot tubs, spas or swimming pools.

The Importance Of Calibrating Your Water Thermometer

Accurate temperature monitoring is vital when it comes to enjoying your pool or hot tub to the fullest. This is where the calibration of your water thermometer becomes crucial, as it ensures precise readings you can rely on

Using ice water is the most effective calibration method, as it provides a reference point for the freezing temperature of the water.

Calibrating water thermometers will help you with the following tasks: 

  • Maintaining optimal water conditions in your bathtub, hot tub or swimming pool
  • Preventing potential safety hazards associated with incorrect water temperature readings (risk of burns)
  • Saving energy by avoiding unnecessary overheating and reducing electric costs
  • Protecting your investment in your pool or hot tub by ensuring optimal performance and durability of the water thermometer
  • Maintaining accurate readings specific to the environment when using a fish thermometer
  • Providing accurate remote monitoring and control of water temperature for those using Wi-Fi-enabled hot tub thermometers or remote thermometers

By understanding the importance of calibration and following some simple steps, you can optimize the performance of your thermometer and make informed decisions about water temperature adjustments.

The Guide to Using Ice Water to Calibrate Thermometer

The Guide To Using Ice Water To Calibrate Thermometer

🧊 To begin the calibration process, prepare a container of ice water. Fill a bowl or glass with a blend of water and ice cubes, forming a slush-like texture.

🧊 Next, carefully insert your thermometer into the ice water, ensuring that it is entirely covered. Let it sit for a few minutes, enabling the thermometer to adapt to the temperature of the ice-cold water.

🧊 During this time, the thermometer should stabilize and provide an accurate reading of 32 degrees Fahrenheit or 0 degrees Celsius, which is the freezing point of water.

If your water thermometer does not show the expected temperature, it may require mechanical calibration. Look for a small screw or calibration dial on the back or side of the thermometer. By using a screwdriver or your fingers, make slight adjustments to the screw or dial until the thermometer displays the correct reading in the ice water.

Remember to be gentle and make slight adjustments to avoid damaging the thermometer. It’s a good practice to repeat the calibration process at least once a season or whenever you suspect your thermometer may be displaying inaccurate readings.

If you own a digital or remote hot tub thermometer, the calibration process for these advanced thermometers may vary, so refer to the manufacturer’s instructions for precise guidance.


In this article, we’ve explored the differences between mercury and electronic water thermometers, highlighting the pros and cons of each type. Whether you’re looking for a water thermometer, a fishing thermometer, or a bath thermometer, we’ve got you covered.

We’ve provided you with our top three picks for the best mercury water thermometers and two options for the best electronic water thermometers. And for those who want to monitor their hot tub temperature remotely, we’ve even included our pick for the best remote hot tub thermometer. We hope that this article has helped you make an informed decision about which water thermometer is right for your needs.

SplashTech Floating Buoy Pool Thermometer
SplashTech Floating Buoy Pool Thermometer
Milliard Floating Pool Thermometer
Milliard Floating Pool Thermometer
Intex Pool Thermometer
Intex Pool Thermometer
Game Digital Pool & Spa Thermometer
Game Digital Pool & Spa Thermometer
Ambient Weather Wireless Floating Temperature Reader
Ambient Weather Wireless Floating Temperature Reader
The most accurate readingsThe cutest designThe cutest designThe easiest-to-read displayThe best protection against overheating


🤒 Can I use a standard thermometer for water?

While a regular thermometer can be used to measure water temperature, it is advisable to choose a specialized water thermometer due to potential limitations. Water thermometers are waterproof, and offer better accuracy and precision, especially for rapidly changing temperatures.

⏳ How long does it take for a thermometer to read water?

A water thermometer is designed to quickly read the temperature of the water, usually taking just a few seconds to provide an accurate measurement.

🔝 How accurate is a water thermometer?

Water thermometers are generally accurate in providing temperature readings, but their precision can depend on the brand and calibration. It is recommended to calibrate your water thermometer for better accuracy.

💧 Can water damage a thermometer?

Water itself does not normally damage water thermometers specifically designed for use in water. However, prolonged contact with water for a thermometer that is not fully waterproof can lead to potential damage or inaccurate readings.

Leave a Comment

Your email address will not be published. Required fields are marked *

Peter Rossi