CAVOK

When the following conditions occur simultaneously at the time of observation:

visibility of 10 km or more, and the lowest visibility is not reported

(Note 1: In local routine and special reports, visibility refers to the value(s) to be reported in accordance with International Civil Aviation Organization (ICAO) Annex 3 4.2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value(s) to be reported in accordance with ICAO Annex 3 4.2.4.4.)

(Note 2: The lowest visibility is reported in accordance with ICAO Annex 3 4.2.4.4.);
no cloud of operational significance; and
no weather of significance to aviation as given in ICAO Annex 3 4.4.2.3, 4.4.2.5, and 4.4.2.6;

then information on visibility, runway visual range, present weather and cloud amount, cloud type, and height of cloud base shall be replaced in all meteorological reports by the term "CAVOK."

Note that this term is not approved, nor will be used, in the United States.

ICAO, 2007: Meteorological Service for International Air Navigation. Annex 3 to the Convention on International Civil Aviation. 16th ed., International Civil Aviation Organization, 187 pp. Accessed 18 November 2020. Available at https://www.wmo.int/pages/prog/www/ISS/Meetings/CT-MTDCF-ET-DRC_Geneva2008/Annex3_16ed.pdf.

Term edited 18 November 2020.

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