CAVOK
CAVOK (Ceiling and Visibility OK) is a meteorological term used in aviation weather reports (METAR) and forecasts (TAF) to indicate that conditions simultaneously meet all of the following criteria: visibility is 10 km or more; no cloud below 5,000 ft or below the highest minimum sector altitude, whichever is greater; no cumulonimbus or towering cumulus; and no significant weather.
What CAVOK Means Operationally
CAVOK is the best possible METAR/TAF weather code — it means the sky is essentially clear, visibility is excellent, and no significant meteorological phenomena are present. For VFR pilots, it is a green light. For IFR pilots, it means an approach will almost certainly be visual.
CAVOK vs. SKC vs. NSC
- CAVOK: Visibility ≥ 10 km, no cloud below 5,000 ft, no CB/TCU, no significant weather
- SKC (Sky Clear): No clouds detected; does not necessarily mean visibility ≥ 10 km
- NSC (No Significant Cloud): No cloud below 5,000 ft and no CB; used when automated station cannot report CAVOK but conditions are similar
On the TC Written Exam
CAVOK is commonly tested in the METAR/TAF interpretation section. Know all four criteria that must be simultaneously satisfied. A METAR reporting CAVOK is always the best-case weather scenario.