What does PWINO indicate in a METAR?

PWINO in a METAR indicates that the precipitation identifier is inoperative. This notation is important as it informs meteorologists and flight dispatchers that the automated weather reporting system is unable to accurately report on precipitation. When this occurs, any references to precipitation conditions should be treated with caution since the information may not reflect the actual weather situation.

Understanding PWINO is crucial for making informed operational decisions regarding flight safety and scheduling, as precipitation can significantly impact visibility and runway conditions.