Best Hygrometer 2018: Review Of Thermo, Indoors, Digital, Most Accurate and more!

by | Jan 17, 2016

Have you ever drove a car without a speedometer? I don’t think so. Well, using your growing equipment without a proper thermometer humidity meter is not a good idea either.

Although we can sense if it’s more or less hot or moist inside our grow space, these feelings are often just impressions we have at a given time, and don’t reflect the climatic reality of a 24 hours cycle, let alone of a full grow session lasting months.

As a few degrees and little changes in humidity levels can make a great difference in your final yield and a thermo-hygrometers is basically a pretty cheap piece of equipment, it’s ALWAYS a good idea to have a reliable thermometer and humidity monitor in your setup (for example if you are setting up 4’x4′ growing tent×4-setup-guide)

List of Best Hygrometer on the Market Today


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What is a Hygrometer?

Humidity is one of the biggest barriers to a successful marijuana grows operation indoors. Humidity is the measure of water vapor in the air. The humidity level in the grow room affects the amount of evaporation in the cannabis plant. Plants thrive in rooms with low humidity levels as seedlings when they’re busy absorbing more water and nutrients (buy seeds online). Later during cultivation, he plants prefer a more humid atmosphere. When humidity levels rise, the cannabis plant closes its stomata and as result, often times experience a growth stunt. The hygrometer ensures that the humidity levels in your grow room are perfection for a successful plant grow during each of the various stages. Monitoring the humidity levels in the grow room almost guarantee a healthy, thriving plant.


Each stage of the growing process is best with a different humidity level. Since your plant suffers greatly in humid conditions and during non-humid conditions, it is important that you’re aware of the right levels during each stage. Furthermore, it is imperative that you gauge those humidity levels using more than an educated guess. Besides, your guess cannot pinpoint the humidity levels and temperature in the grow room as well as a hygrometer. When there is a hygrometer at your disposal you can easily monitor the humidity levels in the room during each stage of cultivation, minimizing risks of a suffering plant. The hygrometer is an easy-to-use product that works by placing it over the top of the plant to record humidity levels.

What Type are you Looking For?


Three types of hygrometers are available for humidity level testing. Each type of hygrometer has its own pros and cons. Weigh the advantages against the disadvantages to determine which of the styles is best for your needs. It is worthwhile to invest in a quality hygrometer. Not only do you get more accurate results with a high-quality hygrometer, you gain confidence that your plant thrives during each growing stage. The three types of hygrometer thermometers that you can pick from include:


  • Mechanical: The mechanical hygrometer is sometimes called an analog or a dial hygrometer. This style uses a dial display to report the humidity measurement. The product is reliable, durable, and measure temperature in addition to humidity levels.
  • Digital Hygrometer: The digital hygrometer provides easy-to-use accuracy in fast times. You’ll need to charge the hygrometer and replace batteries when the time comes.
  • Psychrometer: This is a mechanical hygrometer that uses two thermometers to measure humidity levels. One is a dry bulb and the second is a wet bulb. The dry bulb measures air temperature and the wet bulb measures the liquid temperature. This type of hygrometer is amazing for a marijuana grow, ensuring most accurate results.

The digital hygrometer is the product of choice for most growers. There is a versatile selection of digital models to choose from, and its ease of use and accurate results are sure to benefit you as well as it has so many others before you. The decision is always yours to make, however, so do take the time to learn more about each type of hygrometer to ensure that you choose the most appropriate product.

Features to Compare When Buying a Hygrometer


Dozens of hygrometers are available to purchase, whether you prefer the digital model or a mechanical model. Choosing from these various hygrometers can be a challenge and when you need a product to test humidity levels during a grow, trial-and-error is not acceptable. Rather than risk harm to your plants, first understand your needs in the product and second, take the time to conduct a bit of research before diving right into the purchase.


Features of hygrometers vary considerably from one product to the next. When you understand your needs in the product, it alleviates the time-consuming process of sorting through the different hygrometers to find the best. Some of the features to look for when buying your hygrometer include:


  • Does the hygrometer read in Celcius or Fahrenheit? Do you prefer one reading style over the next?
  • Is the product portable?
  • Can you multitask while using the product
  • Is it easy-to-use and is the display easy-to-read?
  • Does he hygrometer offer a console sensor?
  • Is the hygrometer designed for indoor or outdoor use?
  • Does the hygrometer offer humidity level testing at regular intervals?

Important features to consider when choosing your hygrometer:


  • Design: Hygrometers are small instruments that vary in size and shape. Some are round, some are square, and others are rectangular. Is there a design style you prefer over the next?
  • Brand: Some brands are better known than others because their products are of a higher quality. When choosing a hygrometer for cannabis grows indoor, it is imperative that a trusted, reputable brand is chosen. There’s a greater assurance that comes when you know the brand looks out for their customers best interests.
  • Margin Error: The margin error level indicates the accuracy of the humidity level reading. This error number ranges from 1 to 10. Choose a hygrometer that offers a low error margin level for precise readings and appropriate humidity levels.
  • Battery Life: The battery life of a digital hygrometer is important to consider before purchasing. The longer-lasting the battery life, the less stress you’ll endure using the product.
  • Features/Functions: With so many hygrometer choices, don’t settle for a product that doesn’t meet your needs for features and functionality. Know what you want in the product and find a model that offers what you need.

Finding the Best Hygrometer

Finding a great hygrometer isn’t as difficult as some would assume. Sure, there are many products to choose from, but once you understand your needs and conduct research, the best hygrometer seems to appear in front of your eyes, like magic. The Internet is a free tool that has an abundance of information that alleviates the stress of choosing the right product. Use this information to your advantage.


Be sure to ask fellow growers and friends for advice. More often than not, fellow growers are happy to share their knowledge with others. And, of course, any good friend is ready to help whenever they can help. Social media is an excellent tool that provides first-hand insight into user thoughts and opinions, brand information, and more. Use each of these tools to your advantage to simplify the process of selecting the best hygrometer.

Top Seven Hygrometers

Start your search for a great hygrometer with one of the seven models below. These products are recommended and always deliver accurate, professional results. The plants that you’re capable of growing extends when you have the right hygrometer in hand.

1. Extech 445715 Big Digit Hygro-Thermometer

Buy Extech 445715 Big Digit Hygro-Thermometer

  • Humidity: 10 to 99% RH
  • Temperature: 14 to 140°F (-10 to 60°C)
  • Accuracy: ±4%RH; ±1°C/1.8°F
  • Max/Min with reset function
  • Complete with built-in stand, mounting bracket, sensor, and 1 AAA battery; optional calibration salt bottles

A very popular item with external probe at a decent price. It has a memory for the highest/lowest values, can be calibrated after some time with an additional kit and unless you plan to use it in a sauna, it does the job quite correctly!

2. Extech 445814 Stationary Hygro Thermometer Psychrometer with Audible Humidity Alert

Buy Extech 445814 Stationary Hygro Thermometer Psychrometer

  • With Certificate of Traceability to NIST
  • Large triple display of relative humidity, temperature and dew point
  • Alarm with programmable set point gives visual and audible warning when humidity level exceeds high or low limit
  • Built-in stand for sitting on a desk or mount on a wall using included bracket
  • Recalls minimum and maximum readings
  • Ideal monitoring device in humid areas where mold can be a problem

This unit is just a little more expensive and has no external probe. However, the large displays allows a comfortable reading, it has a memory and the best indoor humidity monitor including an additional humidity alert you can set for yourself, allowing you to react in case of high or low humidity.

3. Ambient Weather WS-07 Big Digit 8-Channel Wireless Thermo-Hygrometer

Buy Ambient Weather WS-07 Big Digit 8-Channel Wireless

  • Includes an indoor thermo-hygrometer in the console and can remotely read and update up to eight remote thermo-hygrometer sensors at the same from the large digit, uncluttered jumbo display
  • Includes one remote thermo-hygrometer and seven additional sensors can be added (F007TH) for comprehensive monitoring
  • The uncluttered display console displays temperature and humidity with jumbo 1.25″ LCD characters which can be easily read from across the room
  • The scroll mode allows you to view the indoor thermo-hygrometer and remote channels without pressing any buttons. In scroll mode, all of the indoor and detected outdoor sensors will be displayed in five second intervals
  • Each remote sensor includes dip switches for channel selection and units of measure (deg F vs. deg C)
  • Includes an indoor thermo-hygrometer in the console and can remotely read and update up to eight remote thermo-hygrometer sensors at the same from the large digit, uncluttered jumbo display.
  • The WS-07 includes one remote thermo-hygrometer and seven additional sensors can be added (F007TH) for comprehensive monitoring.

This device takes climate control to the next level. It’s cheaper than the two previous ones and offers more. The unit is composed of a main console, featuring a thermo hygrometer and a large display, which allows you to connect and monitor wirelessly up to 8 more sensors, one of them being offered. A good option if you have several grow rooms.

4. Ambient Weather WS-10 Wireless Indoor/Outdoor 8-Channel Thermo-Hygrometer with Three Remote Sensors

Buy Ambient Weather WS-10 Wireless Indoor/Outdoor 8-Channel

  • One indoor thermo-hygrometer inside the console, and three remote thermometer-hygrometer sensors (F007TH), all displayed at the same time.
  • The display console can remotely read and update up to eight remote thermo-hygrometer sensors.
  • Includes audible and visual alarms when temperature and humidity exceed your pre-set minimum and maximum alarm settings.
  • Includes three remote thermometer-hygrometers, and five additional sensors can be added (F007TH, F007TP, F007T, F007PF) for comprehensive monitoring.
  • The console displays temperature and humidity, minimum and maximum temperature and humidity, which can be manually reset.

This is the high end device. As the previous one, it’s designed to allow up to 8 additional wireless sensor connections. The screen is larger, it displays up to 4 sensors at the same time allowing you to have a fast overview, and it features visual and audible alarm for preset temperatures and humidity levels. This is the best hygrometer for indoors, with the best indoor temperature monitor in our selection, obviously handy for big scale growers!

5. ThermoPro TP55 Digital Indoor Hygrometer

Buy ThermoPro TP55 Digital Hygrometer Indoor Thermometer Humidity Gauge


The ThermoPro TP55 is one of the most popular hygrometers used by growers today. Its small size is one of the highlights users appreciate, though it is the nearly perfect readings that really give the product its claim to fame. The indoor unit measures within a +/- 2% RH range. Users will tell you that it indeed provides the accurate readings and measurements needed to help marijuana thrive. The product can detect humidity levels from 10% to 99% RH and measures reading in Celsius and Fahrenheit.


The easy-to-use hygrometer has a large, easy-to-read four-ich digital display. The display has a backlit that the user can push when in low light so there is no need to disturb the plant by turning on a light. The backlight is touch screen operational, adding even more simplicity to the product. It makes it easy to measure humidity levels without worry. Plus, it is easy-to-install onto the wall or can be used on the tabletop if you prefer.


You can use this hydrometer with the assurance that you’ll get an accurate reading of the humidity levels and the temperature in the room. It features wet/dry icons for easier use. And, there are icons that indicate if the humidity level is just right, too high, or too low. The product is customer recommended and has earned an above-average rating.


Since the product is small in size, it is easy to use in tight spaces. It is sleek and stylish in design and is always easy-to-read. It is built using strong materials, so durability is yet another concern that is out of your worry zone.



  • Professional accuracy of 2-3%RH
  • Trusted brand
  • 1-year warranty
  • Easy to mount
  • Touchscreen
  • Humidity level measurements every 10-seconds
  • Current trend feature



  • We didn’t find one

* This hygrometer is as perfect as it gets

6. AcuRite 01083 Pro Accuracy Indoor Temperature and Humidity Monitor

Buy AcuRite 01083 Pro Accuracy Indoor Temperature and Humidity Monitor


It is easy to understand why the AcuRite 01083 is a customer recommended product. It has an easy-to-read display, provides accurate humidity and temperature level readings, and has an abundance of additional features. All of this is provided in a digital monitor that is durable and long-lasting. This is in part due to the professional grade sensors in the product.


Although this is a digital monitor, There is a calibration feature that manually records the high and low data for the prior 24-hours of usage. This feature is valuable to growers who want to better predict when humidity is at its best and when it is at its worst. This is a feature that, like the rest of the product, is simple and easy-to-use.


Where do you want to place your hygrometer? Three placement options make it easy to choose the perfect location for your needs. You can place the hygrometer on the table and use it in a tabletop design. The unit is also wall mountable or can be used with a mounted magnet design. Any time that you want to change the location of the hygrometer, it is a simple and easy adjustment.


Everything needed to start using the product is included inside of the box. This includes three AAA batteries, the unit, and an instruction manual. It is easy-to-use, though it is best to spend a few minutes browsing the manual to familiarize yourself with the product. Even if you’ve used hygrometers in the past, each one is unique.


This monitor is designed to use indoors and works wonderfully to determine the humidity levels in the room. With its price tag (less than $20,) warranty and customer recommendations, it is safe to say this unit has surpassed the expectations of many growers and can provide the same results for you.



  • Durable
  • Accurate readings
  • Affordable



  •  Includes only a limited 1-year warranty

7. AcuRite 01080 Pro Accuracy Indoor Temperature Hygrometer

Buy AcuRite 01080 Pro Accuracy Indoor Temperature and Humidity Monitor


The AcuRite 01080 Pro Accuracy indoor hygrometer lacks a lot of styles, but what is misses in design, the product makes up for in humidity detection. It measures indoor humidity levels from -4 to 158 F with a 1 – 99% RH. The easy-to-read display has large numbers so you need only to give a quick glance to read the levels. It is professional and customers love that it is so accurate. The hygrometer features manual calibration so you can always ensure the latest, most accurate information. It even displays the high and low information for the previous 24- hours.


One of the highlights this product offers is the built-in alarms. It is easy-to-program these alarms to alert you when the humidity levels in the room are out of the desired ranges that you’ve set. The level indicator also helps you determine if the danger zone is nearing. You want a 25% RH level of less if you need a dry environment, a 25% – 55% range for a comfortable humidity level, and 55% RH or greater for a high, humid environment.


Easy mounting options give the product versatility of location. And, it is small sized so it easily fits inside any grow room. It works for both small and large rooms alike. The product includes a one-year limited warranty. All of the equipment needed to start using the product is included in the box.


Customers love the product because it has lots of features and because of its ease of use, accurate readings, and comparable to many of the costlier products sold today. As a customer recommended product, it is safe to say that this hygrometer will exceed your expectations.



  • Affordably priced
  • Easy-to-use
  • Accurate humidity level readings
  • Easy to calibrate
  • 10 – second intervals measurements



  •  Does Not use decimal point readings

How Does A Hygrometer Work?

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