At a glance from the code of that page, it looks like it is using regex to eat that page and pull the vars. This works, but it really isn't a good way to do things. The reason it isn't a good thing to do and the reason why that code doesn't work is that as the HTML code changes on the other site, the regular expression used needs to change. Another side of this is you would probably want to write a cache into you code, so that you don't have to access the other website everytime you page is accessed.
So what would I do? I would find a feed from either the NOAA/Weather.gov or use an aviation feed. What you need is something that is alway put out in the same format. Aviation feed may be easiest to find. A metar is a standard airport weather description. I am sure if you do a google search for "PHP METAR Script" so one will have one you can steal and modify for your needs.
