This glossary is written for virtual airline and flight simulation use within Virtual Air Canada Airline. It is not intended as a real-world aviation reference.
METAR
Meteorological Aerodrome Report
A Meteorological Aerodrome Report is a standardized coded weather observation issued by airports at regular intervals, typically every 30 or 60 minutes, to describe current surface weather conditions. The METAR format is defined by ICAO and used worldwide, with minor national variations. A standard METAR includes the reporting station identifier, time of observation, wind direction and speed (and gusts if applicable), prevailing visibility, runway visual range where relevant, present weather phenomena (such as rain, snow, fog, or thunderstorms), sky condition (cloud layers and coverage expressed in oktas, with heights in hundreds of feet), temperature and dewpoint, and altimeter setting. When conditions change rapidly between routine observations, a special observation called a SPECI is issued.
Decoding a METAR requires familiarity with the abbreviated codes used for weather phenomena and cloud conditions. For example, “TSRA” indicates thunderstorm with rain, “FG” is fog, “BKN014” indicates a broken cloud layer at 1,400 feet, and “SN” is snow. The altimeter setting (QNH in hPa or in inHg) is critical for setting the correct pressure on the altimeter to maintain accurate altitude readouts below the transition altitude. METARs are used by flight dispatchers for route planning, by crews during the pre-flight weather brief, and by ATC and approach controllers to determine which approach procedures and minima apply.