The AirTag comparison is interesting. AirTag tracking is clever and results in Apple not knowing the location or identity of either the AirTag or the phone reporting it. This relies on rotating keys that can be seen as random, or at least not identifiable.

But rain or other objective information? I suppose it works, maybe a bit like “limit IP address tracking” — cloudflare or other edge provider could mediate so Apple gets the data, knows it comes from an iPhone (to prevent bad data attacks), but Apple can’t tell what phone sent which data.

(the privacy concern being documentation of when you were inside/outside/etc).