Can Hubitat set lights to the correct color temperature/brightness as they turn on, or is high-to-low flicker unavoidable?

[bertabcd1234]

@nlundqu

The issue is not strictly with the apps. The problem is that the command to turn the light on is always delivered long (comparatively) before the app processing to set the correct color temp and brightness level. From what I currently understand about the Hubitat system it is impossible to make an app that can solve this problem.

But you made it sound like you could do this from the device detail page:

@nlundqu

I've confirmed when setting their color temp (with optional level) directly from the device driver (or hue app) they transition to that desired color/brightness from off, rather than turning on at the previous state.

If you can do it from there, an app could, too. Apps just run the same commands you can run yourself. One of my questions:

@bertabcd1234

what specific sequence of commands on the device detail page does what you want

was an attempt to figure out what that was for you on the device detail page, and another:

@bertabcd1234

Can you share more information about what [the app] is and the specific configuration where you see this behavior,

was an attempt to figure out what the app you're using might be doing.

Knowing these answers would still be helpful. I just thought of the fact that it may also be helpful to know if you have the V2 API enabled in the Hue Bridge Integration app, as behavior may differ in the new API.

As for what Hubitat is sending, unless your app is explicitly sending an "on" before the "set color temperature" command (why knowing the above would be helpful), this is likely just an artifact of how the Hue API works, as I mentioned above. Hubitat is just sending something like this over the API, and that is apparently how Hue interprets it if that's what you're seeing and that's all the app is telling the driver to do (this is a "Set Color Temperature" example, assuming V2 API is enabled):

{"on": {"on": true}, "color_temperature": {"mirek": (1000000/your new color temperature)}}

This is all as a single command, sent at once, to Hue. It seems you are making the assumption that this is not how things are already happening, but it certainly is at the driver level. Again, the app you're using would matter, hence my wondering.

The "prestaging" thing I also mentioned above might help with the rest of this, but you'd still need some care with how your app handles it, since this is not standardized (and the "how" could very well be "not at all," so you'd need a rule or other approach as I also mentioned). That sounds like what Home Assistant offers, and there are plans to look at this in the future. However, in the meantime, I'd look at the alternative I offered that already works:

@bertabcd1234

activate a scene

In my experience, Hue does respond by immediately recalling the set state with no visible transition, though it's possible this could vary by device (none of my Hue bulbs do it, though, FWIW).