I can get the default cities to work, no problem, in the new ROM with the HHC. The main problem I have been having is the custom database wouldn't get data for cities I created in the custom database. It would try and find data and then timeout.
I found someone who found a weather plugin fix, it seems. I have the new ATT ROM 6.1 loaded on a Tilt. Follow the instructions at
*Updated* HTC Weather Patch Not Working? Try This. - Page 6 - xda-developers in post #52 using the mentioned .zip file in post #54. I can now make custom cities to my hearts content, as long as they are valid accuweather sites (as found by going to accuweather.com and putting in the city name/zip code you are interested in). It's nice to have it back...
Thanks to all who share the wealth!!