Is a 1500-foot ceiling that varies in height by 300 feet considered a variable ceiling?

A ceiling is defined as the height of the lowest layer of clouds or the height of obscuring phenomena above the ground. For a ceiling to be considered "variable," it must fluctuate significantly over time within a specified range. In meteorological terms, variability often involves a significant and consistent change, usually defined as a range greater than a specified amount, often twenty-five percent of the ceiling height or a measure that approximates a significant operational impact.

In this particular scenario, while the ceiling of 1500 feet varies by 300 feet, this does not automatically classify it as a variable ceiling. The variation of 300 feet on a 1500-foot ceiling is actually 20% of the ceiling, which is not considered substantial enough to deem it variable under standard definitions. Therefore, a ceiling that fluctuates within this specific range does not exhibit the level of variability required to be classified as such. Thus, the answer is that it is not considered a variable ceiling.