What is the function of a METAR report?

A METAR report serves the critical function of providing real-time, up-to-date information about the weather conditions at an airport. It is typically issued at regular intervals, usually every hour, and includes essential data such as temperature, dew point, wind direction and speed, visibility, precipitation, and any significant weather phenomena. This information is vital for pilots and air traffic controllers as it allows them to make informed decisions concerning flight operations, including takeoff and landing conditions.

The focus of a METAR on reporting current surface conditions differentiates it from other types of weather information, such as forecasts or long-term summaries. For instance, a 7-day weather forecast would not provide immediate data about current airport conditions, and alerts for severe weather, while important, represent a different category of communication. Additionally, long-term weather patterns are typically summarized in documents that do not provide the hourly updates that METAR reports deliver. Thus, the function of a METAR is uniquely centered on reporting the present and immediate weather conditions relevant to aviation safety and operations.