Weather Underground is a commercial
weather service, which provides real-time
weather information via the
Internet. Weather Underground provides weather reports for most major cities across the world on its website, as well as local weather reports for newspapers and websites. Most of its
United States information comes from the
National Weather Service (NWS), as
federal law specifies that information from that agency falls within the
public domain. The website is available in many languages, and customers can access an
ad-free version of the site with additional features for an annual fee.