I believe this is caused when yahoo splits that
zipcode / city up into differnt weather reports or
the city is found in multiple states.

On yahoo's site it lists options of differnt locations
in such instances and the users is expected to drill down
by clicking one of the links.

I've added an if statement to make it quit nicely.
Maybe I'll reqrite it using one of the modules KM has
pointed out.

-scribe