SwitchBot IP65 Indoor Outdoor Hygrometer Thermometer Wireless 3Packs, 100m Bluetooth Range, Refrigerator Thermometer, Dewpoint/VPD/Absolute Humidity Sensor, 2-Year Battery Life, Free Data Storage

I have tried a few Bluetooth weather devices, and this Switchbot is the cheapest and best.Physically, its advantages over similar devices are that it uses standard batteries (2xAAA, supplied) rather than a semi-random type of button battery, and that it is demonstrably waterproof - it is a smooth white plastic box and the battery compartment lid has a seal round it. Also, the nylon hanging loop won't rot and is better than a hole in the back meant to go over a hook or a nail.I was surprised, for such a cheap device, to find that it supports firmware updates, as there was a notification in the app on the first Bluetooth LE connection. It updated in a couple of minutes from v0.4 to v0.5 - an odd version number for a released product - and, as is almost always the case now, there was nothing to state what the update fixed or improved. But the facility is important. In fact, there were four firmware updates in three months and it is now at v0.9. The app is also updated every few weeks, and there is the option to try out beta versions.The Bluetooth signal is evidently good, and not entirely line of sight - I can transfer data into the app from a room about 60 feet away with the device slightly hidden round a corner of the house. From a window 30 feet away, the transfer speed roughly doubles.Caching is well implemented and only new readings are transferred unless you explicitly clear the cache from within the app; this greatly speeds up everything as the device quickly accumulates thousands of readings. When I got a new phone it took 20 minutes to transfer all the readings.Its accuracy is better than that of my Bresser weather station, which cost about five times as much but tends to underestimate temperatures.Another Switchbot advantage, although it gets puzzlingly low ratings in Google Play, is the app. It looks good unlike many similar apps, is simple to set up and use, and data export is easy - select a date range and readings are exported to a comma separated values file in a defined time step. Exporting a reading every minute gives a huge 1.7MB/month file, but exporting a reading every half hour amounts to 50KB/month.I can produce graphs very easily from the exported file - the large graph is an import into LibreOffice with two changes (graph size, and colour and weight of temperature line) - and the other two graphs show what Switchbot can display using its own facilities.I have doubts about the accuracy of the battery level stated by the app, as it remained at 100% for a long time and had only declined to 94% after three months. If taken literally that would mean new batteries would be only be required in late 2028, which is improbable.I find that weather data gathering managed by an app is better than using a weather station, the whole genre now looking outdated with clunky displays and locked-in data, and the Switchbot is an excellent data gatherer. If it could record barometric pressure as well as temperature and humidity, it would replace everything weather-related here. I use a second (ancient) Android phone to provide a semi-permanent display.A minor issue is that the instructions state that the temperature sensor is good to -20C, but the device is recommended only to be used at 5C or greater. It has been down to -4C, with whole days below 5C, and I have noted two missed readings in four months, which were both when the temperature was well above 0C.Most impressive was that I discovered a bug when exporting. I raised a ticket in the app; there was a comment about three days later that it was being "escalated to senior technical staff", then after six days there was a fix! That speed of response is otherwise unheard of in my experience, where technical comments are often not even acknowledged.£15 (sometimes as low as £11) is an absolute steal for something which would have cost several times as much for the same functionality, less well implemented, a few years ago.

Really all I needed was a replacement for a simple, broken outdoor thermometer but I saw these SwitchBot devices on Amazon at a very affordable price. Even more affordably you can get a box of three for around £20 so I went for this option. They come with AAA batteries pre-installed (estimated lifetime 2 years) and a specified operating temperature of -20C to 60c although ‘best between 5C and 50C’. The instruction manual was probably designed for the Queen’s Dolls’ House but is fairly easy to follow with a Q code for setting up the app on iOS or Android. Connectivity is via Bluetooth which should provide adequate coverage but needs a bit of experimentation if, like me, you have an old house with very solid walls.So why a ‘weather geek’? Well what I didn’t appreciate when I bought the devices was the remarkable amount of data they not only provide but also store. They measure temperature and humidity about every 15 minutes and store these measurements internally so that on your phone you can get the current readings immediately for all thermometers or within a second or two your can see on a graph how the measurements have changed over the past hour, day, week or year. These data can also be exported as csv files. I haven’t tried that at yet - and probably won’t. Even mor geeky the devices compute and display such things as Dew Point and Vapour-pressure Deficit which can be a gripping topic at any dinner table.Better still for the real geek, a few more pounds will buy a SwitchBot Hub Mini which puts the Bluetooth readings onto your server so that they can be viewed remotely: handy if you can also control your Central Heating remotely, as I am able to do although not via one of the many SwitchBot additional tools.

For me, this is a 5* product. I’ll get into why after I explain the 4*. One of the indoor / outdoor sensors in my pack of three unfortunately failed its firmware update out of the box and became bricked. Thankfully, support have been amazing and sending me a replacement. The process was little hassle. That being said, I feel out of principle I cannot give a 5* right now.The product itself is brilliant. Compact (actually smaller than I was expecting), which makes it unobtrusive and good to put in tighter spots or even inside things (a terrarium for example). Connectivity is excellent. No hub or even an app are needed for this, you can hook it straight into home assistant over bluetooth. However, the switchbot app is great and has a lot of useful functionality. One of my favourite things about this is that you can just use it or take it with you anywhere and check temp and humidity on your phone. I’m a bit of a data nerd so i’ve taken it to all sorts of different places in the short time i’ve had it.Accuracy is hard to gauge without a benchmark I know is 100%, which i don’t have. But I believe they are very accurate, and did my research before hand to make sure they would be. Having a number of these sensors, they seem to agree strongly with one another. Which is reassuring. The one thing I will mention, is that their time to adapt to a drastic change in temperature +-20 celsius is quite long. Perhaps 20 mins or maybe a bit more. This is no issue, as the accuracy is stellar. But for some others this may be a concern.Overall, i’d highly recommend these.