Although conkyForecast is an excellent script, (and should be the first step for anyone who wants weather in their conky) when I recently reformatted and lost all my conkyForecast files I wasn't too keen on going through the weather.com registration again.
So I've been looking at alternate ways of getting weather, particularly getting pretty icons. One was is here
http://crunchbanglinux.org/forums/post/104686/#p104686
look a few posts down for the code, although seeing as it is specific to my local weather station for the weather and the images, it probably wont work for you.

also out of this i had a way of drawing rounded corner boxes which I have further developed in various background scripts.
With the weather there is also time and date and system info. Everything is generated in a Lua script. Not only do I find it easier, I find it is lighter on resources than running code from the conkyrc.
An example of that is here
http://crunchbanglinux.org/forums/post/115451/#p115451