You sticker and code is correct.
edit - Looks to be correct as far as I can see. It seams the Underground Weather server is not updating. Only a couple of their demo stickers are updating right now.
Here is the code for the one above
[url="http://www.wunderground.com/cgi-bin/findweather/getForecast?query=Council Grove, KS"
][img]http://weathersticker.wunderground.com/weathersticker/defaultorig/language/english/US/KS/Council_Grove.gif[/img
][/url]