When does a TAF cease to be valid?

A TAF (Terminal Aerodrome Forecast) ceases to be valid once it has surpassed its issued validity period. Each TAF comes with a specified time frame during which it is applicable, typically covering a 24 or 30-hour period, depending on the specific forecast. Once this time frame elapses, the TAF is considered outdated, regardless of whether the weather conditions have changed or improved.

While the issuance of a new TAF or new information might lead to the use of a different forecast, these situations do not impact the validity of the previous TAF until its designated expiration time. This is important for aviation safety, as pilots and air traffic control make decisions based on the most current and valid information available. Understanding the timeframe of TAF validity is crucial for ensuring that users are relying on appropriate weather predictions during flight operations.