Review: WeatherFlow Tempest – A weather station is not only a nice device for amateur meteorologists to be able to see when it is raining or what the weather forecast is for your location. If you really want to automate your home, a weather station is also a handy addition. With this you can, for example, have sun blinds or windows closed, activate the lighting or adjust the irrigation in the garden accordingly. In this review we look at the WeatherFlow Tempest, a weather station with numerous sensors. We also use this weather station in our Smart Living Project, in which we are going to make a house completely smart.
What is the WeatherFlow Tempest?
WeatherFlow is an American company that has been dealing with the weather for years. The company has already launched several weather stations and announced the Tempest in early 2017. This innovative artificial intelligence product was launched through Indiegogo and I took the risk at the end of 2019 to support the project as well. Last November, the Tempest finally arrived, no less than three years after its announcement.
The Tempest is WeatherFlow’s most advanced weather station to date. The device has artificial intelligence, which basically means that different algorithms process all data from weather stations on a daily basis, which is then checked for accuracy. This allows WeatherFlow to perform new calibrations on a daily basis to optimize forecasts for any location (any weather station).
The weather station is fully equipped with various sensors. There is, for example, a light sensor that measures the ambient light, the UV values and the solar radiation. The pressure sensor measures the air pressure at sea level and at station level, while the lightning sensor measures the number of lightning bolts and the distance to the lightning. The temperature sensor measures the temperature, the humidity sensor measures the humidity and the sonic wind sensor measures the wind speed and direction. Finally, the haptic rain sensor measures the amount of rain and the intensity. The Tempest also has solar panels that continuously charge the device, provided the sun is shining. So there is no nutrition available.
The WeatherFlow Tempest is used in combination with the Tempest app, where all data can be viewed. There is also integration with various smart home platforms, including Google Assistant, IFTTT and Homey. The Tempest can be purchased from the WeatherFlow website for $ 329. In addition, we purchased the ‘Bird Deterrent’ accessory for a few dollars extra, which are simply some pins so that birds do not sit on it.
Design and installation
When you think of a weather station, you probably see separate modules for wind, rain, etc. mounted on a pole in front of you. The Tempest is not a standard weather station in terms of appearance as everything is contained in one compact device. It is a sleek device, which is neatly finished but naturally stands out. The station is about 30 centimeters high and 18 centimeters in diameter. The Tempest only comes in a white version.
In addition to the Tempest outdoor unit, the kit also comes with an indoor unit, which is a small white router-like device that can be placed anywhere indoors. The outdoor unit and indoor unit communicate wirelessly, according to WeatherFlow at a distance of up to 300 meters.
The placement of the outdoor unit is an important part. In the accompanying app and on the website WeatherFlow explains the optimal placement of the Tempest, but it depends on the use. Is the focus on rain? Then close to the ground is better. Is the focus on wind? Then a higher placement with a lot of free space is important. All kinds of variables also influence the correct placement. For example, choose a place where the sun comes out a lot and where there are not many obstacles in sight. The ideal location is not there, especially in more densely populated areas, but WeatherFlow provides a guideline with sufficient sunlight, at a sufficient distance from ground, walls or other obstacles that can affect data. A height of 1.5 to 2.5 meters from all obstacles (ground, wall, roof, etc.) is recommended. We have placed the Tempest in the back of the garden, as far away from the houses as possible and about 1.
You can screw the weather station to a tripod, clip it to a wooden construction with a screw, or simply tighten it to a PVC pine with a diameter of 32mm or 33mm. We have used long PVC pipes attached to the garage wall. You screw the Tempest firmly on it with the supplied attachment. The whole should not move too much as this can result in incorrect data.
Another important aspect of the placement is the direction in which the solar panels point. At the back of the Tempest is a blue arrow that must point to the geographic north. This is not the same as magnetic north, so you have to figure out where geographic north is in your garden. Point the arrow in that direction and the wind direction will be registered correctly. The solar panels also receive the most sunlight. And that sunlight is important, as shown later in the review.
WeatherFlow Tempest app
The Tempest app is the place from which you control your weather station and where you can view all data. This can also be done online in the browser, in a comparable environment. Installation is a piece of cake. You create an account with WeatherFlow, set your location, give your weather station a name, add the altitude of the station and connect your WiFi network. Within minutes, the data starts to pour in.
The home screen of the app is the screen with the current weather situation and the forecast. All information you see here is based on the data of your own Tempest, combined with data from other users and international (official) data. A local weather forecast is compiled by means of algorithms, forecast models, machine learning and a baseline.
The tab ‘history’ shows the minimum, average and maximum values per data per day. For example the minimum, maximum and average temperature. The ‘settings’ tab gives access to all settings. For example, you can activate notifications for ‘rain start’, ‘lightning’, ‘Status online / offline’ and ‘quality check’. You can also set the scale or unit for all data. For example, you can choose from Celsius and Fahrenheit for temperature and for wind you can choose from km / h, m / s, BFT, LFM, mph and kts. If you click through to your own weather station, you can change the name, adjust the location, adjust the height and activate the option to make the data from your weather station public. The latter makes it possible, for example, to add your Tempest in Weather Underground as a weather station. In the advanced settings, you can turn off lightning detection and manually adjust the offset for the wind direction. Rain Check is an option that helps calibrate the rain recording by looking at the rain recorded by nearby stations. This option does not work in Europe yet. All in all, there are plenty of setting options, but some are a bit difficult to find. The structure of the app could have been better.
Finally, from the home screen you can click on the icon of the Tempest at the top right to access all data from your station. There is an awful lot to read and see on this page, including temperature, dew point, humidity, air pressure, air pressure trend, wind speed and direction, mm of rain of the day, UV value, the brightness, the solar radiation and even the voltage of the built-in battery. If you click on one of the boxes with data, you can dive even further into the data by means of graphs. Here you can zoom to a view of 5 minutes, or zoom out to a view per week or day.
Sensors – Accuracy and Capability
The WeatherFlow Tempest has numerous sensors that provide insight into everything about the weather. According to WeatherFlow itself, this is done very accurately, with, for example, a maximum of 2% deviation for the humidity, 5 degrees deviation for the wind direction and 0.2 mm / h deviation for the rain intensity. The sensors must self-calibrate and also learn from other WeatherFlow stations and official measurements.
Of course it is all difficult to check as the data is specific to the location of your Tempest, but comparing with weather stations in the area and the weather forecasts and data from official weather services can go a long way. That’s why we added our Tempest to Weather Underground. This way we can compare our data with dozens of stations in the area.
The Tempest seems to perform the same in most cases and sometimes better than many stations in the area. Looking at the temperature, humidity and wind there is not much difference and the values are almost in line with official weather stations. The Tempest is closer to this than some hobbyist weather stations in the area. However, in the case of the wind, obstacles and houses in the area can regularly cause a difference between stations. Yet the trend is always comparable. The amount of light and solar radiation usually also correspond. The light sensor is sensitive enough to not suddenly display very low values during a dark cloud, so that the lighting switches on while it is actually still light enough. The sensors measure gradual changes perfectly. Lightning was detected correctly and quickly 99% of the time, and it is a really nice addition to know the distance the lightning is about.
The haptic rain sensor is all that takes a little patience and work. This sensor registers the ticking of the rain and determines the size of the drop on the basis of this. This works differently from the traditional rain sensor, which is a container that collects water. The haptic sensor for registering rain is relatively new and not quite perfect yet. This was also evident from the fact that our rainfall values deviated drastically from those in the environment. Light rain was recorded while it rained heavily. An email to WeatherFlow was enough for the company to help immediately and dive into the values of my and surrounding stations. Based on this, the rain sensor was remotely recalibrated, which is done for all users who wish to do so. The calibration result was not good. Suddenly, too much rain was recorded, causing our Tempest to report 18mm after a rainy day, while other stations were at 8mm. Another email to Tempest and another new calibration seems to have found a good balance. With very light rain (drizzle), the drops are sometimes still too small or too few drops have fallen within the surface of the sensor that no rain is registered, but in general the rain that really matters is recorded well and accurately . On the other hand, it must be said that the start of a rain shower is sometimes faster recognized by the Tempest than by stations in the area. The Tempest is also able to indicate the intensity of the rain shower, in millimeters but also by means of terms such as ‘light rain’. That is a function that many weather stations do not have.
In any case, it is clear that the rain sensor requires a personal adjustment and does not always work well from the box. WeatherFlow also admits that they are still working hard on the perfect adjustment for the haptic sensor. It is therefore worthwhile to compare the values of the sensor with those in the environment in order to arrive at a correct adjustment together with WeatherFlow. It is certainly not perfect yet, because then very light drizzle must also be recognized. This is especially important when you automate your windows for rain. 20 minutes of drizzle can also cause a wet floor.
Incidentally, the notifications from the Tempest app work fine. As soon as rain is registered you will immediately receive a notification. The same goes for lightning and the notification that the Tempest is offline (more on this later). It is also good to know that all data is updated every few seconds, depending on the sensor concerned and the status of the internal battery.
Battery life and solar energy
The WeatherFlow Tempest is a weather station that is completely self-sufficient. The device has a number of solar panels that automatically charge the internal battery. There is therefore no possibility on the device to connect an external power supply. The folks at WeatherFlow are Americans from Florida and the sun shines so often and powerfully there that it hasn’t really been thought about. Because in Northern Europe the sun is not there very often, especially in winter. Then the sun is low and it is often not even visible through the cloud cover.
The solar panels in the Tempest require 4 hours of solar radiation of at least 350 w / m2 to fully charge the device, according to WeatherFlow. Then the Tempest should last about 2 to 3 weeks on a full charge. That is not a big problem in the summer, spring and autumn in the Netherlands. There are always a few days with the minimum solar radiation, and even if it is spread over a few days, the Tempest will still be recharged a little. But … winter is a different story, as we immediately noticed. In December we still had a few days with some sunshine (200-250 w / m2 for a few hours) which caused the Tempest’s battery to creep up a bit, but since the beginning of January the sun has barely come through. This has ensured that our weather station has been offline for about 10 days. There was simply not enough sun, despite the fact that we have already placed the station a bit higher. The sun is too low and not strong enough, and it is also often cloudy. The Tempest has been online again since last Friday (January 22). On that day the radiation was above 200 w / m2 for a few hours and the voltage has increased to 2.40 volts. This means that the weather station will last a number of completely cloudy days.
his is the Tempest’s main minput, especially for users who are not in sunlit areas. This can mean that you are without a weather station in winter. Fortunately, a solution is being worked on. WeatherFlow promises to come up with an accessory this spring that will give the Tempest extra nutrition and should be able to last much longer without sunlight. What that accessory will cost and when exactly it will appear is not yet clear.
Smarthome integration
The fact that the WeatherFlow Tempest is a modern weather station is evident from the wide smart home integration. The device can be connected to numerous platforms, left or right.
First of all, there is integration with Google Assistant and Amazon Alexa for voice control. Or at least: requesting data. You can request a weather report or simply request the temperature. But, unfortunately, this ‘talk with WeatherFlow’ function only works in English for the time being and only when the Google Assistant is also set up in English. That is of course a shame, but according to the company, they are working on broader employability.
Another way to control the Tempest with all your smart home devices is IFTTT . Thanks to this integration, you can use the data from your weather station to, for example, control the lighting or control the windows. IFTTT always makes a link possible to the left or right. For example, we make the Hue lighting blink at lightning.
More importantly, WeatherFlow uses an open API. This means developers can build integrations themselves. For example, it is possible to link your Tempest to the Homey smart home hub and to use all data for your own automation. The possibilities are therefore endless. Other integrations based on the API are Crestron, openHAB, HomeSeer and Home Assistant. For the future, WeatherFlow has announced that it is working on Siri Shortcuts and integration with SmartThings.
Conclusion – WeatherFlow Tempest
The WeatherFlow Tempest is one of the most modern weather stations for home use. The weather station is versatile, compact and equipped with the latest sensors that provide very accurate data. You will receive a tidal wave of data that can be used to compile your own weather forecast. Thanks to an open API and IFTTT, you can then easily use that data to control equipment in and around the house.
Nevertheless, there are certainly points for improvement. For example, the Tempest is dependent on solar radiation, which is not very common in the Netherlands during the winter months. Chances are that this will cause the Tempest to go offline. A new accessory with extra backup battery will be released for this this year, but that means an extra expense. In addition, there is a good chance that the rain sensor is not properly adjusted from the box. It is advisable to compare the data from the weather station with weather stations in the area and request a calibration from WeatherFlow on the basis of this. Fortunately, the support from the company is very good, fast and friendly. Finally, the Google Assistant integration does not yet work for Dutch users. The device is also not cheap at $ 329, but with the user-friendliness,
Are you looking for a versatile and modern weather station that provides accurate data and offers possibilities to serve as a basis for various smart home applications? Then the WeatherFlow Tempest is definitely recommended. However, we do recommend that you purchase the (yet to be released) battery backup as an accessory, at least before the winter of 2021 starts.
- Accurate data
- Large amount of data
- Modern and sleek design
- User friendly
- IFTTT and open API
- Very good support
- Google Assistant only in English
- Not enough sun in the Dutch winter
- Battery backup accessory required
- Rain sensor may require calibration
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