I know the feature is announced since long and many are waiting (me included 
) . Not sure when this will come from the design board (also Matter being there and not really mature)
As we have some very coders here, I stumbled on this. Could some bridge be coded around this project ? I use it already for my security cam integration that isn’t supported natively by Homekit. Works like a charm.
I’m not a coder but will help test if someone feels like trying. 
Why not just use HomeBridge and the existing WF-T integration???
https://github.com/chasenicholl/homebridge-weatherflow-tempest
Let’s say my other things are not very well handled in HomeBridge (the plugins are way outdated and not using the HomeKit as it could).
I also didn’t quite like that Homebridge plugin — it works well but is not integrated as nicely into HomeKit as I’d like
I found GitHub - naofireblade/homebridge-weather-plus: A comprehensive weather plugin for homebridge. and saw that somebody was working on a PR that added local Tempest Weatherflow support … and I helped land it, it’s shipping since a month and works very well: Release 3.3.0 · naofireblade/homebridge-weather-plus · GitHub 
Much more detail, much more control, but you will need to use the Eve, Home+ or Controller app to set up automations using it.