5 Best Greenhouse Thermometers of 2024

If you want an easy way to check on the temperature and humidity, day or night, this ThermoPro TP55 Temperature and Humidity Monitor has a clear screen and useful backlight.

When the ‘lightbulb’ button is pressed, using the touchscreen display, the LCD screen will illuminate for approximately 15 seconds. This gives reasonable time to take a reading, without wasting too much battery. It’s therefore useful for checking temperature and humidity data at night.

The numbers for both the temperature and humidity are sufficiently large and easy to read, and the screen clearly displays other information as well. At a glance, directionally arrows indicate whether the temperature/humidity is dropping or rising, and the unit automatically interprets whether the humidity percentage is considered within ‘dry’, ‘comfortable’ or ‘wet’ levels.

It’s also possible to view the maximum and minimum figures for ‘all time’ or in the last ’24 hrs’. However, it is worth mentioning that there is no programmable clock inside this monitor; therefore, the 24-hour counter begins when you put the batteries in, not at the start of the day. This could be inconvenient if you’re trying to keep an eye over the data over a standard day period.

There are options to either hang the monitor, or prop it up on its own stand. Therefore, you can easily move it around and keep it on any surface, including shelves in the greenhouse.

In terms of accuracy, it seems to generally perform well as both a temperature and humidity gauge for non-professional use. It measures temperature in increments of one decimal place and the manufacturers state that it is accurate to ±1°C.

The display is larger than many similar thermometers, and the dimensions of the whole unit are approximately 8 x 11 cm. Taking this size into account, as well as the clear screen and functional backlight, this is one of the best greenhouse thermometers if you want something easy to read in all conditions.

There is only one minor issue with the backlight, which is worth mentioning – it needs to be turned on via a small button on the touchscreen. And naturally, in the dark this is difficult to see. Therefore, it can take a while to press the correct button to illuminate the display.

Sometimes, all you need is a basic, water-resistant thermometer like this Brannan Digital Max Min Greenhouse Thermometer. It doesn’t overcomplicate things, simply displaying the current temperature, as well as the maximum and minimum.

It’s robust in its simplicity, and its green ABS plastic case has a water and dust resistance rating of IP65 – this makes it suitable for use outside in the greenhouse as well as indoors. IP65 is considered both dust tight and protected from ‘low pressure jets’; as result, it should stand up against humidity, rain and even the odd accidental splash from the hose.

Unlike some of the units featured on this list, this Brannan thermometer doesn’t measure humidity, but it does still display the maximum and minimum temperatures. These are easy to read, displayed in numbers that are the same size as those displaying the current temperature. Resetting the max and min temperatures needs to be done manually, using a small button on the side of the unit.

This button can be a little small to press, especially with gloves on.

However, continuing with the theme of ‘simplicity’, there are only two buttons in total; the other allows you to alternate between Fahrenheit and Celsius depending on your preference. It will measure within the ranges of -10 to +50° in either unit.

It requires 1 x AA battery to run, which comes included, and can be set up in a matter of minutes. All things considered; this is one of the best greenhouse thermometers if you want something easy to use. Its design is simple and uncomplicated, with the added benefit of being waterproof.

Greenhouses aren’t renowned for having loads of free space, which is why it helps that the ThermoPro TP50 Temperature and Humidity Monitor is a particularly compact device – measuring just 7.8 x 6.6 cm. It fits roughly into the palm of your hand.

It can be positioned wherever there’s sufficient space, with a hanging option as well as a built-in stand and magnetic back. If you’re really low on room, you could even attach it to a metal watering can.

Even though the unit is compact, it still clearly displays humidity and temperature readings. On top of showing the current data, it also shows ‘low’ and ‘high’ readings from the last 24 hours, and indicates whether the humidity is considered ‘dry’, ‘comfortable’ or ‘wet’.

Compared to the small Brannan Greenhouse Thermometer, the ThermoPro TP50 is capable of measuring a much larger range of temperatures, from -50°C to 70°C, and it can display its readings in either Celsius of Fahrenheit.

According to the manufacturers, it’s accurate to ±1°C, and reports from customers seem to support this claim. Whilst not precise enough for professional use, it should give a good overall impression of the temperature and humidity inside the greenhouse.

Unlike its larger sibling, the TP55 (also featured on this page), this TP50 doesn’t have a backlight so it’s not particularly easy to read in the dark. Nevertheless, with the use of a torch it should still be easy enough to interpret main data; despite this unit’s small size, the numbers are still quite large.

It’s one of the best greenhouse thermometers if you need something small and compact. Plus, it has the added bonus of people able to affix to many different surfaces, depending on where will save the most space.

It requires 1 x AA battery, which comes included.

One of the best greenhouse thermometers if you’re after value for money, this Thermometer World Max Min Thermometer has a simple, clear screen that displays three sets of data.

In the middle, the largest numbers show the current temperature. Then, above and below, the maximum and minimum temperatures are displayed as well. These can be measured over any period of time, as they are reset manually.

It’s a useful tool to have hanging in the greenhouse, and the manufacturers claim that it is accurate to ±1°C. This makes it suitable for working on a variety of tasks, such as keeping an eye on max/min temperatures during seed germination.

The plastic casing is relatively robust, and has a hole cut out in the top that makes the thermometer easy to hang. However, unlike some of the other thermometers featured here, it doesn’t have an official waterproofing rating – rain can get inside if it’s left outdoors in the garden. Nevertheless, it seems to work well in greenhouses without being negatively effected by humidity.

Whilst the design has a built-in ‘roof’, this doesn’t do much in regards to protecting the thermometer from either rain or sun, and it’s best to keep it out of direct sunlight as well to avoid overheating.

This thermometer is straight forward to use and comes with 1 x AAA battery included which is all that’s required to start it running. It’s sufficiently accurate if you want a small, easy-read thermometer that offers good value.

It can also be changed between Celsius and Fahrenheit depending on your preference.

Budget thermometers can be wildly inaccurate, but this Outback Blue Digital Min Max Thermometer gives a useful reading whilst being clear, easy to use, and yes – inexpensive.

In appearance, its design is similar to the Thermometer World device also featured on this page, with an almost identical shape and layout. This Outback Blue Thermometer measures 15 x 7.5 cm and displays the current temperatures, as well and the maximum and minimum temperatures.

There are also two buttons on the front that are easy to use and see; one button is for alternating between Celsius and Fahrenheit, and the other for resetting the max/min temperature.

It has a white plastic casing, described as ‘water resistant’. Most customers seem to have found this description accurate, and that the thermometer is not easily affected by small amounts of moisture, be that light rain, or humidity inside the greenhouse.

In terms of accuracy, it generally seems to be correct to ±1°C, so whilst not a professional device, it’s useful for general gardening. The total temperature range available is -50°C to + 70°C, although it can get a little less accurate during very hot summer temperatures.

Overall, taking into account this thermometer’s accuracy, ease of use, and cost, it’s one of the best greenhouse thermometers to buy on a budget. Whilst it might not be as precise as more expensive thermometers, it offers good quality and for the price and will provide useful readings.