[Apple] HomeKit Integration

Thanks for the very comprehensive answer. I guess my concern would be Apple implementing support for other data (e.g. wind speed) in HomeKit in the future and being stuck with a device that only supported legacy HomeKit data (e.g. temperature), but I guess if a device is HomeKit certified, you can still expose new data to HomeKit now even if at this time, it’ll just ignore it? Or would you need to understand Apple’s device-specific HomeKit implementation before you could bake it into an existing product in anticipation?

Right, my understanding is that you can add custom characteristic types (like wind & rain) but the Home app will ignore them and other apps must build in support directly for them.

You would, but presumably we would be able to add support for future characteristics with a firmware update (not a hardware change).

If, for example, we added custom support for wind & rain and other parameters, and then Apple later released official support for those parameters, we would be able to support them as well with a firmware update. That’s the hope anyway - no guarantees when it comes to the HomeKit spec!

Out of curiosity, what is it you are trying to do? Maybe it can be done without HomeKit.

At this time I don’t have a specific use-case in mind (so I need to be careful I’m not wishing for something that I’m never going to have a practical use for), but I can see potential for this type of data, even if it’s very basic (e.g. turn the garden sprinkler off if it’s raining, send me an alert if the wind speed reaches a limit).

I’m trying to move more of my home automations into Home now it’s beginning to mature (slightly!) so I’m not having to deal with multiple manufacturers’ apps and services like IFTTT. Besides, I quite like the Applesque simplicity of HomeKit, despite its limitations (which are maybe good for reigning-in some of my automation-for-the-sake-of-it ideas). However, even if Apple do expand to support weather stations, I do wonder how useful they would be as event triggers given that HomeKit data has no historical context - if a single drop of rain falls on a sensor, I suspect HomeKit would consider that as “rain detected” even if it was the one and only drop all day. Even if HomeKit could process accumulated rainfall, hitting a 10mm total over a 24hr period gives no indication of how heavy it was actually raining when the device hit that threshold - 9.99mm could have fallen much earlier in the day. I guess it would really depend whether HomeKit was pulling raw or derived data fields from the devices.

Anyway, it’s somewhat academic right now until I can get my hands on a Tempest in the UK :slight_smile:


The free Eve app can apparently get 27 different weather observations and weather forecast values out of this HomeBridge plugin, which also offers some hackish mappings into fake (virtual) devices to access some of the unsupported values in Apple’s Home app:

If you do not have HomeBridge installed yet, I highly recommend using the HOOBS free Raspberry Pi Linux distro:

I’m running HOOBS in a Docker container on my Synology NAS, as a bridge between HomeKit and my Hubitat home automation system. With all of the plugins available for HomeBridge, the Hubitat could almost just be a Z-Wave bridge.

Speaking of plugins, feel free to write one for the WF PWS and forecast APIs, using the above as an example…


Add me as well, new Tempest owner here.

Those 3 specifically would be useful to me. I will control shades based on outside temperature and radiance for example.

For the custom attributes, am I able to use those to control automations in Homekit directly?

You actually can’t use those three parameters yet in the Home app to trigger actions. You can only view them. You need a third-party app to do anything useful with those three parameters.

No, you would need a third-party app that was aware of the custom attributes or a customizable solution like HomeBridge.

Both of these issues are what make HomeKit nearly useless for home weather stations at the present time. Services like IFTTT are much more useful.

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With IFTTT’s recent subscription cash grab and an alleged insane surprise price increases for service providers, how much longer can we expect IFTTT support to be around???

The recent user pricing changes at IFTTT are definitely a blow to growth and open the door for alternatives to come along. Our provider pricing is quite reasonable and could go up quite a bit before we’d even consider abandoning it. But don’t tell them I said that :slight_smile:


I’d also love to see HomeKit integration and am a bit surprised it’s not there, especially given other (maybe lesser) weather stations offer it. I’d also imagine slapping a HomeKit badge onto the Tempest would help it sell even better.

HomeKit support is still a moving target, I’m afraid. Yes, there are a handful of weather stations with the badge on the box, but it’s mostly marketing. Since HomeKit does not support outdoor weather parameters, yet, there’s not much you can do with it. We’re watching developments closely and hoping Apple offers real HomeKit support for weather data soon.


HomeKit does support outdoor temperature and humidity, which are valuable data points for home automation routines:

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That’s true, HomeKit does provide some support for temperature and humidity - thanks for the correction @vreihen. I should not have said it doesn’t “support outdoor weather parameters” because HomeKit doesn’t care if your T/RH sensor is indoors or out. What I should have said is that HomeKit does not currently include the concept of a weather station, nor any parameters a weather station measures other than temperature & humidity. The T & RH services are grouped with HVAC stuff (thermostats, heaters, coolers, fans, filters, etc).

More importantly, the other issue is that HomeKit support is limited to viewing T & RH values in the Home app. So (unless something’s changed recently), you can SEE the values in your Home app, but you can’t USE those values to create automations or do much else because they are not considered “triggers” by HomeKit or the Home app. If that’s not true, please correct me.

Regardless of all this, we still very much intend to support HomeKit! As I’ve explained previously, the current Hub was supposed to support it. It DID support it when we first designed it, but Apple changed the rules (and dramatically increased the hardware requirements) before we could finish the implementation. That hardware, even though it includes the special Apple MFI authentication coprocessor, no longer has enough oomph to run the HomeKit code. Our friends at Netatmo have a similar story (though it looks like theirs was even more frustrating than ours!).

I’m sorry if it sounds like I’m making excuses - I guess I am! :slight_smile: But we are pressing forward!! The Pro Hub, which continues to be delayed for a number of different issues, has the extra processing and storage power (along with the MFI coprocessor) that it needs to support HomeKit. So, unless Apple moves the goal posts again, the Pro Hub will be able to support HomeKit. We have even completed a proof-of-concept with a prototype Pro Hub where the Tempest Hub could control a HomeKit light bulb (it was an exciting moment!).

Thanks for your understanding and patience!


Is it acting as a “hub” that can run its own automations to control HomeKit devices, as a workaround to Apple’s refusal thus far to let temperature be used as an automation trigger?

FWIW, third-party iOS apps can trigger scenes (but not trigger devices) based on temperatures, if someone really wants to go that route. Personally, I use a dedicated HA hub for all of my automations, and only use HomeKit as a Siri UI from my Apple Watch via HomeBridge…

No, the PoC was one of their reference applications, which simply confirmed we could do “HomeKit things” with the hub hardware. We are not planning to have the Tempest Hub run as a general HomeKit “hub” - the plan is to simply expose the data to an existing HomeKit environment. And hopefully Apple will come around and add a set of weather station service specs.


God’s Speed on integration with HomeKit, God’s Speed!!!

Add my vote to the list as well. I use Apple HomeKit for home automation as well. It would be another perk for the Tempest system. Not sure what it will take for the developer to add the feature. I know it takes some time meet Apple’s standards and to get Apple’s approval for HomeKit compatibility, but it would be a welcomed feature. Voted!

Can’t it just be a generic sensor? Temp, wetness, lux? Or does it have to do with certification that I be “outdoor” doesn’t Philips Hue outdoor motion sensors have many of the same type sensors types?

Perfect settings at home is only possible with a good weather station.
And only with accurate data you can perfectly control the irrigation and set the air conditioning to the right temperature.
This way you can also save energy.

That’s why I am for a FULL INTEGRATION in HomeKit.

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Gets my vote - please continue to consider this and/or Matter support.