What is the key difference between SKC and CLR in weather reporting?

The key distinction between SKC (Sky Clear) and CLR (Clear) in weather reporting lies in the specifics of their definitions and the contexts in which they are used. CLR typically refers to conditions where there are no significant obstructions to visibility, often standardized as a condition of having clear skies up to a specific altitude, often 12,000 feet in automated reporting systems. In contrast, SKC is used to indicate a clear sky with no significant clouds detected, but it is generally considered a visual observation that emphasizes that there's an unobstructed view of the sky.

Thus, the assertion that CLR is an automated report made up to a height of 12,000 feet, while SKC is reported manually, accurately depicts their differences. It's important to understand that these classifications serve different functions in aviation and meteorological communications, ensuring that pilots and meteorologists can interpret sky conditions accurately depending on whether the report is generated automatically by equipment or through manual visual observation.