stupid question: no weather component has data for this in its forecast. so where do you get the data from?

please test your stuff before you create a PR

Which came first, chicken or egg? In this case both: home-assistant/core#13971

Link the PR in the description please and add screenshots

Thanks for reopening. I've referenced the other way around and this is visible on the website. But you're right, it's not visible ie in the OctoDroid Android App.

Currently there is no unit for the values, but this is a problem for the temperatures as well. The openweathermap precipitation is in mm. Should we at this to the HTML?

we have units defined here hass.config.core.unit_system -> length. for metric we use [mm] for precipitation

... and imperial uses inch/in.
the conversion (if required) should be done by the backend part

Ok, thanks I'll look into it. But I meant if the unit should be visible.

Backend PR was merged. Maybe we do the unit thing in a second PR.

getUnit(measure) {
  if (measure === 'precipitation') {
    return this.getUnit('length') === 'km' ? 'mm' : 'in';
  }
  return this.hass.config.core.unit_system[measure] || '';
}

what about the more-info-card? https://github.com/home-assistant/home-assistant-polymer/blob/master/src/dialogs/more-info/controls/more-info-weather.html

Don't know if every weather provider gives this value as mm/inch or if we get rain probability and therefore should pass the unit together with the data.

Then you should check this

I solved the merge conflicts in #1221, If we get problems with incorrect units that should be fixed in main repo components