What does "CAVOK" stand for in METAR reports?

"CAVOK" stands for "Ceiling and visibility okay." This term is used in METAR reports to indicate that the weather conditions are acceptable for flying. Specifically, it means that visibility is 10 kilometers or more, there are no significant weather phenomena, and that there are no clouds below 5,000 feet above ground level or below the highest minimum sector altitude.

This is significant because when CAVOK is reported, pilots can interpret that the weather does not pose immediate issues for operations, such as approaching or landing at airports, making it an important piece of information within METAR communications. The other options do not accurately reflect the specific terminology used in aviation meteorology, which is crucial for maintaining clarity in reports related to flight safety.