National Digital Forecast Database Web Service Use Guidelines

Access to the services is through an infrastructure with limited resources.  As the popularity of the service has grown, NWS has added capacity as resources allow.   A challenge of offering these services is also a strength: the creativity of our customers to use these services in ways never imagined.  This creativity can also strain our resources at times.  Below are some guidelines of use:

• It is recommended a client not make more than one request every five seconds;
• The forecast data is updated no more than once an hour: never request for the same location more than once an hour;
• Please request data for only elements (hourly temp, max temp, wind speed, etc) that you need;

Consider using the optional degrib interface to provide XML data on your local systems if:

• You have built a system that generates revenue and you want to assure your customers high availability;
• If you need to make more than 720 queries of the service in an hour;
• If you have created a client application, like a desk top widget that uses the service and you want to ensure customer access;
• If you have developed an application that is mission critical to your operations.

The degrib interface allows for the download of the raw binary forecast data and the running of the degrib client that will output the same XML code as the Internet based web service.