We spent 43 hours on research, videography, and editing, to review the top selections for this wiki. Ideal for gardeners who need to keep their flowers and plants at precise levels, for reducing the risk of mold in potentially damp basements, and for maintaining comfortable room conditions, these humidity monitors provide accurate tracking of moisture in the atmosphere. We’ve included both plugin and battery-powered models, as well as units that also measure the current temperature. When users buy our independently chosen editorial picks, we may earn commissions to support our work.

10. Habor Digital

With a kickstand, a hanging hole, and a magnetic back, the Habor Digital can be installed almost anywhere. Its LCD screen is easy to read, and includes a cute smiley face indicator that shows you whether your room is at a high, low, or normal level.

  • Simple minimalist design
  • Small and compact
  • Doesn’t have any backlighting

Brand Habor
Model GEHM118AB
Weight 1.6 ounces
Rating 4.0 / 5.0

9. Ambient Weather Monitor

The display screen of the Ambient Weather Monitor is backlit in bright orange, making it highly visible when you want to take nighttime readings. It also comes with a waterproof probe that can be used to measure inside refrigerators and freezers.

  • 5-foot cable on the probe
  • Backlighting activates automatically
  • Housing isn’t very attractive

Brand Ambient Weather
Model WS-2063-W-P
Weight 7.2 ounces
Rating 4.0 / 5.0

8. AcuRite Indoor

With multiple mounting options and an easy-to-read LCD screen, the AcuRite Indoor’s black and silver design will blend into almost any room. Plus, it’s compact enough to be placed on the corner of your desk or directly on your fridge or HVAC duct for quick access.

  • Shows highs and lows for last 24 hrs
  • Can be clipped onto a backpack
  • Not as accurate as other models

Brand AcuRite
Model 00613B
Weight 9.9 ounces
Rating 3.9 / 5.0

7. Cigar Oasis Caliber IV

The Cigar Oasis Caliber IV is bright enough to read through the glass of a humidor, and includes a self-adhesive magnet, so you can put it anywhere. It comes out of the box precalibrated, so you know it’s displaying the correct information.

  • Slim housing is easy to hide
  • Rarely needs to be recalibrated
  • Great for continuous regular use

Brand Cigar Oasis
Model SYNCHKG055735
Weight 1.6 ounces
Rating 4.8 / 5.0

6. Amprobe Temperature Meter

In addition to relative humidity, the Amprobe Temperature Meter can measure other environmental factors, like wet or dry bulb temperatures and dew point. It is ideal for HVAC technicians who need a durable model for field testing.

  • Can be mounted on a tripod
  • Includes a carrying case
  • 0- to 100-percent test range

Brand Amprobe
Model THWD-5
Weight 2.3 pounds
Rating 4.2 / 5.0

5. ThermoPro Gauge

The ThermoPro Gauge runs on a single included AAA battery and is compact enough to easily fit on your desk without getting in the way. It indicates whether your air is dry, moist, or comfortable, so you know at a glance when you need to make adjustments.

  • Displays temperatures in f and c
  • Magnetic backing
  • Easy to clear stored readings

Brand ThermoPro
Model Digital thermometer hyg
Weight 3.2 ounces
Rating 4.1 / 5.0

4. Extech Alarm

The Extech Alarm offers several advanced features, like an audible tone that warns you when moisture levels are too high or too low, a probe that can measure in hard-to-reach places, and recall of minimum and maximum readings.

  • Ideal for areas susceptible to mold
  • Also measures dew point
  • Integrated kickstand

Brand Extech Instruments
Model 445815
Weight 7.2 ounces
Rating 4.5 / 5.0

3. HoLife Clock

The HoLife Clock comes in a desktop model and a wall-mountable option, so you can choose the one that best fits your needs. It displays moisture and temperature trends, so you know if your room is getting closer or further away from your ideal levels.

  • Large easy-to-read screen
  • Includes adhesive for hanging
  • Stores max and min readings

Brand HoLife
Model pending
Weight 3.2 ounces
Rating 4.7 / 5.0

1. AcuRite Pro Accuracy

The AcuRite Pro Accuracy works in temperatures ranging from -4 to 158 degrees Fahrenheit, so there are few indoor or outdoor conditions it can’t handle. In addition to current levels, it displays the all-time record high and low readings and those from the last 24 hours.

  • Measures every 10 seconds
  • Can be wall-mounted
  • Color-coded indicator

Brand AcuRite
Model 01083M
Weight 2.9 ounces
Rating 4.9 / 5.0

How Modern Humidity Sensors Work

Humidity simply means the presence of water in the air, and various humidity sensors measure that presence in different ways. Because it is difficult to isolate the water content in the atmosphere, each type of sensor measures some other co-existing quality in the air, like pressure or electrical charge. A capacitive humidity sensor works by monitoring the electrical capacity of a strip of metal oxide. The strip is placed between two electrodes, and when there is a change in atmospheric humidity, the electric charge on the metal oxide alters.

Thermal conductivity sensors are made up of two sensors, one of which sits in dry nitrogen, while the other is exposed to ambient air. The difference between the two sensors’ ability to conduct electricity is an indicator of humidity. Thermal sensors measure absolute humidity rather than relative humidity. Relative humidity is the ratio of water in the air to the amount of water that could be in the air at the current temperature. Relative humidity plays a large role in how comfortable humans feel in certain climates.

Resistive humidity sensors use the ions in salt to achieve their measurements. When there is a change in humidity, there is an adjustment in the resistance of the electrodes on either side of the salt. Resistive varieties sometimes use conductive polymers instead of salt; regardless of the material involved in measuring electrical resistance, these models typically need to be paired with a temperature sensor to achieve accurate results.

Gravimetric sensors use mass to measure humidity. These sensors compare the mass of an atmospheric air sample to that of an equal volume of dry air. Weather experts consider this the most accurate method of determining humidity. The United States, The United Kingdom, The European Union and Japan established national standards based on gravimetric measurements.

What Can Happen When Humidity Is Too High Or Too Low

Humidity can affect human comfort, which is one of the reasons the weather report lists it each day, but it can also do much more than that. Proper humidity levels in greenhouses are crucial to ensuring optimal growing conditions for crops. Most plants hold and move water through their tissues; it is taken up by the roots and sent out through the leaves into the air. This process — called transpiration — is important to cooling a plant down. When humidity levels in the air are too high, transpiration happens slowly and that can harm the plant.

Musicians often use humidity sensors to monitor the environment of their instrument. When humidity rises, the wood in items like violins and guitars expands. During times of high humidity, musicians find it difficult to tune their instruments because the wood around the pegs has swelled, making them too tight. Reversely, if humidity levels drop, the wood of an instrument can shrink, causing tuning pegs to become too loose, and difficult to keep in place.

Humidity is important in spas, gyms and country clubs because these venues typically contain saunas. While the temperature inside of a sauna can rise to 90 degrees, it remains comfortable because the humidity levels are kept low. Most people have experienced this phenomenon in natural locations, too; walking through the desert can be more comfortable than traversing a rain forest, even if the temperatures are the same because the latter has high humidity levels. Businesses that operate steam rooms try to keep the humidity levels up to 100 percent inside of these environments, which is why condensation builds up on the walls. Both of these climates — dry and humid — offer health benefits, but only for short periods of time, which is why warnings are posted outside of each, with suggested usage.

Additional Data Found On Humidity Sensors

Modern humidity sensors can report several pieces of information about the environment. Countless systems run through and around your home, interacting with both the climate inside of your walls and outside of them. If they build condensation, retain too much moisture or freeze, they can fail to work properly.

Some sensors display the dew point — the temperature at which water vapor turns into liquid. An instance in which one can observe this happening is when ice on a window melts into water. That water can sink into the window pane, causing the wood in it to expand and warp. Wood warping can cause problems for the structure of a home. Frost point also appears on many sensors and is the temperature at which water vapor in the air turns into ice. Monitoring the frost point can help prevent issues like frozen pipes. Consider a sensor with alarms that alert you when humidity levels are too high or too low.

People who live in highly polluted areas can benefit from sensors that analyze air quality. Some sensors report the carbon dioxide levels in the air, which can help one determine if air conditioning or heating is escaping. A humidity sensor can also be built into an all-in-one weather reporter, which displays daily highs and lows, humidity comfort levels and local forecasts.

The 10 Best Humidity Monitors