This handbook is designed as a technical reference for all who operate in the National Airspace System (NAS). Pilots, dispatchers, and operators will find this handbook a valuable resource for flight planning and decision making.

This handbook conforms to pilot weather training and certification concepts established by the Federal Aviation Administration (FAA). The discussion and explanations reflect the most commonly used weather products and information.

It is essential for persons using this handbook to also become familiar with and apply the pertinent parts of Title 14 of the Code of Federal Regulations (14 CFR) and the Aeronautical Information Manual (AIM). Title 14 CFR, the AIM, this handbook, current advisory circulars (AC), and other FAA technical references are available via the internet at the FAA home page at https://www.faa.gov.

This handbook is available for download in Portable Document Format (PDF) from the FAA’s Regulations and Policies web page at https://www.faa.gov/regulations_policies/handbooks_manuals/aviation.

This handbook was signed and published by the U.S. Department of Transportation (DOT), FAA Aviation Safety, Flight Standards Service (FS) on April 2, 2026.

The guidance and recommendations in this handbook are not legally binding in their own right and will not be relied upon by the FAA as a separate basis for affirmative enforcement action or other administrative penalty. Conformity with the guidance and recommendations is voluntary only and nonconformity will not affect rights and obligations under existing statutes and regulations.

Comments regarding this publication should be sent, in email form, to the following address: 9-AWA-AFS400-Coord@faa.gov.