I'd personally use SimpleXML for this, you just have to bear in mind the custom namespace which is being used to carry the weather data, here's a little example (with no error handling etc) which I've just tested and fetches the current weather.
//Fetch the feed$feed = file_get_contents("http://rss.weather.com.au/sa/adelaide");//Load it into simplexml$weather = simplexml_load_string($feed);//Get namespace descendants using the w namespace defined in the feed$channelelements = $weather->channel->item->children("http://rss.weather.com.au/w.dtd");//Looping through each of the attributes and echoing them, you can do what you want with them at this pointforeach($channelelements->attributes() as $k => $attr) { echo $k.' = '.$attr.'<br />';}