I was looking at the in-app purchases list and it doesn't explicitly have a family-sharing plan like Weather Line does.

This looks great and I'd definitely consider switching my family Weather Line plan over to an Acme Weather family plan if it becomes possible.

I am on the free trial and it did not extend to my family. Unsure whether this will change when the trial converts to a paid subscription.

Yes please devs, make this subscription shareable with family