Hey Brian,
This is the first opportunity that I have had to reply and post an update to this thread.
I must say that I can report nearly the exact same promising situation that you have experienced with the weather app. After my last post of 17 Jan, I did nothing else to the phone. I did do one other thing after writing that post...I sent Apple an email detailing every aspect of the problem that you, I and other people within this thread and elsewhere were having. The email also contained links to this thread, iClarified's article/thread and the MacRumors thread.
I also went on to explain to them that it was necessary to empasize the connection between the weather app not updating and users of AT&T. I had previously sent AT&T a message with the same information.
The email to Apple was sent late on Jan 17. On the eve of Jan 19, my weather app began to update without any problems....and to this day, it has remained functioning properly.
Will, it last? I certainly hope so...not only for me, but for everyone else!!
As for the emails that I sent to Apple and AT&T...hey, they get thousands of emails a day. I highly doubt that the ones that I sent had anything to do with an apparent resolution of this issue...regardless though, I am hopeful that it indeed IS resolved. However, I will report back here if the issue returns.
Having said that, it is important that anyone, who does experience a technical/customer service issue, keep the line of communication open and flowing and not give up. It is the collective effort of us ALL that will reap a positive result.
Cheers and
All the best to everyone,
joe