I have a family member, who is in her mid 70's, who is obsessed with the weather. She doesn't have dementia, but does have anxiety, socializes quite a bit, attends church, visits with friends, has fairly good health, though she has many psychologically induced ailments, HOWEVER, when it comes to the weather, it's like she is totally obsessed.
During the spring and summer she is constantly watching the weather reports and Weather channel, worrying about storms, wind, rain, lightning, etc. She is so over the top about it. She sits up all night if storms are predicted. Our entire family is aware of this and she knows that a lot of the younger ones roll their eyes and patronize her about it, as she is very verbal in warming others about storms. It really is concerning.
I suppose there isn't much that can be done. She refuses medication, which the doctor has prescribed for her anxiety and she is adamant that she doesn't want to end this obsession! lol I've never known of anyone else like this before.