Air traffic controllers seem to broadcast this information, is anyone able to tell me what this is or what its use is for?

LTBA 162120Z 03008KT 360V080 9999 BKN035 06/02 Q1028 NOSIG

Especially the last part, what does NOSIG mean?

  • $\begingroup$ NOSIG means no significant change since the last update. The information is called a METAR. $\endgroup$
    – Ron Beyer
    Mar 16, 2016 at 21:39

1 Answer 1


This is a METAR (meteorological terminal air report), a routine weather report for aerodromes. NOSIG means no significant changes are expected within 2 hours.

METAR are jointly standardized by ICAO, the international organization for civil aviation and WMO, the international weather organization. Codes used in METAR (also SPECI and TAF) can be found in the reference document from WMO: Aerodrome Reports and Forecasts: A Users’ Handbook to the Codes.

There are also decoders online.


From the Wikipedia article

METAR is a format for reporting weather information. A METAR weather report is predominantly used by pilots in fulfillment of a part of a pre-flight weather briefing, and by meteorologists, who use aggregated METAR information to assist in weather forecasting.

The meaning of this METAR is:

enter image description here

Source: E6BX


A METAR may contain a TREND section to indicate the current weather trend. The TREND period is two hours. From Aerodrome Reports and Forecasts: A Users’ Handbook to the Codes:

A TREND forecast consists of a concise statement of expected significant changes in the meteorological conditions at the aerodrome, to be appended to a routine or special report (METAR, SPECI). The period of validity of a TREND forecast is 2 hours from the time of the report, and this report forms an integral part of the forecast.

The TREND forecast indicates significant changes in respect of one or more of the elements: surface wind, prevailing visibility, weather and cloud. Only those elements for which a significant change is expected are included.

When no significant change is expected to occur, this is indicated by the abbreviation NOSIG


Not the answer you're looking for? Browse other questions tagged .