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The Best Indoor / Outdoor Thermometer Comes From Finland

Proper thermometers are crucial for environmental monitoring, and with environmental monitoring you can ensure correct temperature levels for different temperature sensitive spaces. Unfortunately, most good thermometers are expensive as they are made for professional use. However, a Finnish company has developed and began selling reliable and easy-to-use monitoring technology to consumers. The best indoor / outdoor thermometer is a RuuviTag!

Monitoring temperature is important to ensure correct temperatures for (to name just a few examples): 

  • Refrigerators and freezers
  • Musical instruments
  • Humans and their pets
  • Attics and basements
  • Engine rooms
  • Boats

Moreover, measuring temperature accurately can help you predict upcoming weather conditions, you can find more information here!

In principle, you need thermometers in numerous different use cases and a durable digital thermometer can accurately handle all of these situations! 

So why should you opt for Ruuvi, especially RuuviTag, to be your thermometer of choice?

RuuviTag fits in every fridge
Here is a RuuviTag. RuuviTag is a great choice for a refrigerator thermometer

RuuviTag Has an Accurate Temperature Sensor

A reliable thermometer must be accurate. And, RuuviTag checks that box easily. RuuviTag’s temperature sensor accuracy is ±0,2 °C at 5…60 °C with an output resolution of 0,01 °C. With RuuviTag Pro, the absolute accuracy is ±0,1 °C with an output resolution of  0,01 °C.

Screenshot of a daashboard view of many kinds of envirnomental measurements.
Here is a screenshot from the Ruuvi Station web interface. You must have a Ruuvi Gateway in order to use a web interface

Unless we are talking about scientific experiments, this level of accuracy is more than enough for every use case you could think of!

A Thermometer Exposed to Extreme Temperatures Must be Durable

For a thermometer to be useful in very cold or hot environments, it must be durable enough to withstand tough conditions. From a freezer to a steaming sauna, you want to be able to use the same monitoring system. Digital thermometers must also withstand water if they are to be used outside.

RuuviTags basic operating range is between -20 °C and +70 °C. These temperature limits are set by the CR2477 battery powering the thermometer. The RuuviTag itself withstands temperatures from  – 40 °C to +85 °C, so if you acquire a more durable battery you can easily use RuuviTags in most spaces.

RuuviTag fits in any freezer and is a durable freezer thermometer.
RuuviTag ensures the correct temperature in the freezer

RuuviTag is also IP67 certified. This means that this digital thermometer withstands a brief submerging in water and water splashes. Keep in mind not to place your RuuviTag in spaces with the possibility of condensation for a long period of time as condensation may damage the electronics inside the RuuviTag.

RuuviTag has an even more durable version, RuuviTag Pro, which fits the challenging needs of industrial use. RuuviTag Pro automatically comes with a wider temperature range battery and it’s available in two variables: RuuviTag Pro 2in1 and 3in1.

For water measuring temperature, RuuviTag Pro 2in1 is a fully waterproof thermometer with IP68 and IP69K certifications.

In short, this means that the RuuviTag is suitable to withstand any demanding needs of your temperature monitoring. The battery usually lasts between two and three years, so you really do not have to worry about changing the batteries frequently.

RuuviTag Pro hanging next to sea. A digital water thermometer.
RuuviTag Pro 2in1 is completely waterproof. Therefore it can be used as a water thermometer

Ruuvi Station is a Convenient Thermometer App

RuuviTags are wireless and transfer measurements via Bluetooth. They work straight out of the box together with a free Ruuvi Station mobile application. The application works as a thermometer application displaying current temperature measurements with a refresh rate of a few seconds.

The application is easy-to-use. Most important features of the application are:

  • You can set adjustable temperature alarms so that the app notifies you if the temperature falls below or above the preset values.
  • You can read and examine temperature measurements in a graph form, from the past 10 days. You can also download a CSV-report of all the measurements and gather a larger datasheet using Google Sheets, for example.
  • You can look at the measurements of all of your RuuviTags at a quick glance.
Three views of the Ruuvi Station application. Thermometer app at its finest.
Three views from the Ruuvi Station mobile application

Indoor / Outdoor Thermometer with Hygrometer, Barometer and Movement Sensor

RuuviTag is not just a digital thermometer. Depending on the model, RuuviTag is also a hygrometer, barometer and detects movement. The basic RuuviTag has all of these features.

Measuring humidity is also really important for environmental monitoring. Relative humidity that is too low is bad for our health as well as for wooden instruments and furniture. Excessively high relative humidity can lead to mould growth which is also bad for our health and can damage different structures and objects in our homes and workplaces. 

With a barometer, you can measure the difference in our atmospheric pressure and start to forecast upcoming weather.

With a movement sensor, you can see, for example, if a door opens or an engine is not vibrating correctly.

So while being the best indoor / outdoor thermometer, RuuviTag is also a working solution for many other environmental monitoring problems. The RuuviTag enables the measurement of three additional environmental factors!

Complete Wireless Temperature Monitoring with Ruuvi Gateway

RuuviTags send Bluetooth messages to your mobile phone, which are then displayed in the Ruuvi Station app. This all sounds great, but what if you want to receive measurements and alerts while on the go?

For this problem, we have developed the Ruuvi Gateway. Ruuvi Gateway is a gateway that listens to RuuviTags’ measurements and sends them to the Ruuvi Cloud, where you can access them at all times. These measurements are also seamlessly transferred to your Ruuvi Station mobile application.

Ruuvi Gateway lets you to examinate your measurements wherever you are!
Ruuvi Gateway

With Ruuvi Gateway’s special antenna, the Bluetooth listening range can be in an optimal environment up to 2 kilometres or 1.2 miles!

Examples of Ruuvi as a Digital Thermometer

Here are a few quick examples of RuuviTag as a digital thermometer. There is a vast amount of temperature measuring use cases, so your imagination and creativity are the only limit!

RuuviTag – Thermometer for Refrigerators

Refrigerators should be kept at temperatures between 2 – 6 °C (35 – 43 °F) according to the FDA.

In colder temperatures, food could freeze and also unnecessary energy is wasted. In higher temperatures, food can spoil more quickly. There are surprisingly big differences in temperature between the different parts of the fridge. RuuviTag is small and you can place it anywhere inside the fridge. With its graph function in the app, you can determine the real temperatures in your fridge.

Also, you can set a custom alert for this specific temperature range. If the temperature is too high, it can indicate that the door has been left open. You will be notified and you can close the door before any serious problems occur.

RuuviTag as an Indoor Thermometer

Different rooms in our home should have different temperatures. Sleep is optimal at a temperature of 18 – 20 °C (65 – 68 °F). But, in your living room the comfortable temperature is usually around 21 °C ( 70 °F). In unused rooms temperature does not need to be as high as in livable rooms. Hence, you can make big savings in energy by monitoring those rooms as well. 

RuuviTag as a Musical Instrument Thermometer

Wood is the main material in many instruments. Wood can be damaged in suboptimal temperature and humidity levels. By storing your wooden instruments in the correct temperature and humidity, they remain playable for much longer. 

Best thermometer for instrument monitoring fits in the cases of the instruments.
RuuviTag is a great instrument thermometer


Ruuvi is a Finnish company producing environmental monitoring devices. For the best indoor / outdoor thermometer, you should really consider the RuuviTag. RuuviTag is:

  • Durable
  • Accurate
  • Has a wide wireless range
  • Comes with a free easy-to-use application
  • Affordable

You can place RuuviTags in all of the different places where you wish to monitor temperatures and read their data simultaneously and easily. Sounds very convenient, right?

Where do you need a thermometer?

Ideally, you’d want to keep a thermometer in any area that is sensitive to temperature changes. Ruuvi’s products are made to last and be accurate. With a wide operating temperature range, RuuviTag is the perfect thermometer for you. Get yours now and begin to measure your world!

Can an outdoor thermometer be used indoors?

At least with Ruuvi it can! All of Ruuvi’s sensors can be used indoors and outdoors as they have a wide operating range.

Where should I put my indoor / outdoor thermometer sensor?

You should put it in a place where you need temperature monitoring. For example, an outdoor thermometer should be placed in a shadowy place so that direct sunlight does not hamper the measurement. In indoor use, a thermometer could be used in a bedroom to help find optimal sleeping temperature.

How does a wireless outdoor thermometer work?

RuuviTag is a battery powered thermometer that measures temperature, humidity, air pressure and movement with accurate sensors inside its capsule. Then, it sends these measurements via Bluetooth to a device capable of receiving these messages. These include, for example, mobile phones and the Ruuvi Gateway. With RuuviTags, you do need battery consuming pairing, as RuuviTags only send data on normal mode.

How long does an outdoor thermometer last?

RuuviTags batteries last for approximately two to three years depending on the usage temperature. Once it’s depleted, you just need to replace the battery and the device is good to go for the same number of years again!

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