Apple’s service uptime in general has been taking a bit of a beating in recent months. Similar Apple ID issues have cropped up over the last few weekends, which often presents itself in apps like Apple Music and TV+ as the user being asked to subscribe for the service, even though they actually already do.
The Weather app in particular has seen a lot of downtime, with the latest instance occurring earlier this week.
There is no known workaround for the current Apple ID problems. You simply have to wait for Apple engineers to address the backend server issue and gradually, access to Apple ID services will be restored.