I like how simple it is, but it definitely needs an RSS feed. Seeing as they're using some sort of IP geolocation, it would be cool if the forecast 'followed' me in the feed when I switched locations.
I think "pointless" is going a bit overboard, it's up to the client to decide how long to cache a feed, and the cache policy for the feed should use normal HTTP conventions - the Last-modified, If-modified-since and Expires headers.
If the feed expired in 60 minutes that would be enough to update for changing locations.
