Variable ceiling information is provided in the remarks section when the ceiling is:

The statement regarding variable ceiling information is pertinent when the ceiling is below three thousand feet. In such cases, it is crucial for aviation operations to be aware of changes in cloud heights, which can significantly impact safety and flight planning.

When the ceiling is at such low altitudes, pilots require detailed and timely updates about any variability in cloud layers. The remarks section in METARs and TAFs is specifically designed to supply additional relevant information, such as variable ceilings. This allows aviators to have a clearer understanding of the atmospheric conditions they'll encounter, particularly when dealing with lower visibility and potential obstacles during takeoff and landing.

In contrast, ceilings above three thousand feet are typically considered acceptable for general aviation operations and may not necessitate such detailed reporting. Variable ceiling information is, therefore, less critical at higher altitudes. Having variability detailed in the remarks section is especially vital in managing approach phases of flight, where transitions to lower altitudes occur.