Here's a METAR:

SCEL 090000Z 15005KT 5000 HZ NSC 10/08 Q1020 NOSIG

What does NSC mean?


2 Answers 2


NSC means No significant clouds.

  • 2
    $\begingroup$ Welcome to Av.SE. While your answer is entirely believable, it would be better if you could link to a source to corroborate what you've posted. I don't doubt your answer, but the general expectation here is that answers have some authority to them, not simply "somebody on the internet said it means {this}". $\endgroup$
    – Ralph J
    Jul 9, 2019 at 5:56
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    $\begingroup$ You can just Google it. skybrary.aero/index.php/… $\endgroup$ Jul 9, 2019 at 6:01

WMO Publication No. 306 - Manual On Codes - Volume I.1 - Part A, Section A, FM 15 METAR, FM 16 SPECI:

15.14.14 When no cloud below 1 500 metres (5 000 ft) or the highest minimum sector altitude, whichever is greater, and no cumulonimbus and no towering cumulus are forecast, and CAVOK is not appropriate, the abbreviation NSC shall be used.

Some countries have published different rules:

  • WMO Publication No. 306 - Manual On Codes - Volume II:
    • Netherlands Abbreviation NSC: The abbreviation NSC shall not be used. As appropriate, clouds present at and above 5 000 ft also shall be reported.

    • New Zealand Other than at Auckland (NZAA), Wellington (NZWN) and Christchurch (NZCH) NSC is not used, clouds are reported at all heights and SKC is used to report no cloud.

  • The Manual of Surface Weather Observation Standards for Canada does not have NSC in the METAR definition.
  • AIP USA, GEN 1.7 - Differences From ICAO Standards, Recommended Practices and Procedures, Annex 3 − Meteorological Service For International Air Navigation, Part II, Appendix III:

    4.5.4 ... CAVOK and NSC are not used.

    And the Federal Meteorological Handbook No. 1 also does not have NSC in the METAR definition.


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