Google Calendar's log in page loads a weather calendar (unfortunately, the location guessed by Google is not accurate):

http://www.google.com/calendar/suggest

I think it's a bad idea to prominently display a feature that could show inaccurate information.

Indeed the function puts me also on a wrong location, 117 km off..

It puts me in my ISP's location like every other site that reads my IP, which is again, roughly 120km away.