The Weather RSS feed enables you to get up-to-date weather information for your location. You can save this feed in My Yahoo! or your favorite feed aggregator, or incorporate the RSS data into your own web site or client application. The Weather RSS feed is a dynamically-generated feed based on WOEID.
You might also be interested in http://isithackday.com/geoplanet-explorer/index.php in order to find the WOEID of a city.