Free Weather Forecast Web Service

The National Weather Service has a Web service you can use:

http://www.weather.gov/xml/

To use it:

1. Copy the WSDL:

http://www.weather.gov/forecasts/xml/DWMLgen/wsdl/ndfdXML.wsdl

2. Right-click on the Web site and select Add Web Reference.

3. Paste the WSDL address, from step #1 above into the address bar and click Go.

4. After you see the response from the Web service, which is a description of the service, click the Add Reference button, which will add gov.weather.www to the Web References folder.

5. The following service shows one way to use the service:

        protected void Page_Load(object sender, EventArgs e)
        {
            var weather = new gov.weather.www.ndfdXML();
            var result = weather.LatLonListZipCode("80130");
            var denWeather =
                weather.GmlTimeSeries(
                    "39.5432,-104.939",
                    DateTime.Parse("12/31/09"),
                    DateTime.Parse("01/02/10"),
                    WebTest.gov.weather.www.compTypeType.Between,
                    WebTest.gov.weather.www.featureTypeType.Forecast_Gml2AllWx,
                    "maxt,mint,wx");
            Response.Write(denWeather);
        }

I called LatLonListZipCode to get the LatLon for the specified Zip Code.  Then I passed that LatLon to the first parameter of the call to GmlTimeSeries.  Yep, I cheated by hitting a break point and copying the latlon out of the XML document in result.  denWeather is another XML document that is returned by the service.  You can use LINQ to XML to get the return values and display them on the screen however you want.  You should visit http://www.weather.gov/xml/ for a full description of what methods are available, the meaning of their parameters, and any other information about the API.