A METAR is a routine surface weather observation for an airport, issued in a compact coded format. Its great advantage is consistency: the groups always appear in the same order, so once you know the sequence you can decode any report quickly. A related forecast product, the TAF (Terminal Aerodrome Forecast), uses the same weather codes but adds time and change groups to describe how conditions are expected to evolve.
The standard order
- Station and time — the airport’s four-letter ICAO identifier, then the day and time in Zulu (UTC), ending in Z.
- Wind — direction (degrees true) and speed in knots, with gusts noted by a G.
- Visibility — prevailing visibility, in the U.S. given in statute miles followed by SM.
- Weather — present weather such as rain, snow, fog, or thunderstorms, with symbols for intensity and proximity.
- Sky condition — cloud coverage and height, in hundreds of feet above ground level (for example, BKN030 is a broken layer at 3,000 feet).
- Temperature and dew point — in whole degrees Celsius, separated by a slash.
- Altimeter — the altimeter setting, in the U.S. preceded by an A and given in inches of mercury.
- Remarks — additional detail, introduced by RMK.
Reading one in practice
Work left to right and translate each group in turn. The close spacing of temperature and dew point is worth noting: when they are nearly equal, the air is near saturation and fog or low clouds become likely. A trend toward lower visibility and ceilings across successive reports is an early warning that conditions are deteriorating.
Keep going
The fastest way to build fluency is to decode real reports until the order becomes automatic. For a full key to every coded group — including the less common ones — see our METAR & TAF code reference, and try decoding a live observation with the METAR decoder.