How get today's Weather data for any selected City?

using (WebClient wc = new WebClient())
          {
              string html = wc.DownloadString("http://202.54.31.7/citywx/city_weather1.php?id=43003");
              MessageBox.Show("Maximum Temp :"+ html.Substring(html.IndexOf("Maximum Temp") + 76, 4));
              MessageBox.Show("Minimum Temp :" + html.Substring(html.IndexOf("Minimum Temp") + 77, 4));
          }