For "this doesn't work for me" to be clear, you'll need to explicitly say what "this" is. There are a lot of things in this lengthy thread that "this" could refer to.
The problem is not so much that it defaults to Cupertino and NYC, and is fixable by deleting Cupertino and reconfiguring your weather choices adding any that are missing. The problem is that after re-configuring, apparently successfully, your choices disappear and Cupertino and NYC are back again. This is clearly a bug in the watch OS weather gadget or in Watch OS itself.
New Behavior noticed today:
After fixing this yesterday, the watch showed Framingham as the default, with Rio Grande, Boston and Brattleboro as choices if needed. This morning I read temperature on my watch clock face at 44 degrees. Its warmer than that here, Currently 52. It's Cupertino -- again... The Watch ran out of juice this morning, and I charged it this am. Maybe that's when it changed. I didn't check before bed last night. Wish I had. Turns out Cupertino made it into my list, and was treated as the default . That's new behavior. Previously the whole list was replaced by Cupertino/NYC
Clear documentation of when and under what circumstances the bug re-appears is needed.
I'll be discussing this in a promised phone call from Apple Support on Monday. Stay tuned to this thread.