How to Read a METAR: A Pilot’s Plain-English Guide
A METAR is the single most important weather report a pilot reads before every flight. It is a coded snapshot of the current conditions at an airport, updated roughly every hour (or more often when the weather is changing quickly). Once you learn the pattern, you can decode one in a few seconds.
This guide walks through each part of a METAR in the order it appears, using a real example. If you would rather skip the memorising, our decoder does it for you — but understanding the structure makes you a sharper, safer pilot.
A worked example
Here is a typical METAR for London Heathrow:
METAR EGLL 151020Z 05008KT 9999 BKN032 17/12 Q1023
Let us break it down group by group.
1. Station and time
EGLL is the four-letter ICAO code for the airport (Heathrow). 151020Z means the report was issued on the 15th of the month at 10:20 Zulu (UTC). Aviation always uses UTC to avoid timezone confusion.
2. Wind
05008KT is the wind: coming from 050° true at 8 knots. If you see a G, such as 05015G25KT, that is a gust — here gusting to 25 knots. VRB means variable direction, and 00000KT means calm.
3. Visibility
9999 means visibility is 10 km or more. A four-figure number like 3200 is metres. In the US you will see statute miles instead, such as 10SM or 1/2SM. The code CAVOK (“ceiling and visibility OK”) is shorthand for excellent conditions.
4. Weather phenomena
Present weather is coded with intensity and type. A minus sign is light, a plus is heavy. For example -RA is light rain, +SHRA heavy rain showers, TSRA a thunderstorm with rain, BR mist and FG fog. If the sky is clear of significant weather, this group is simply absent.
5. Cloud
Cloud is reported as amount and height in hundreds of feet. BKN032 is broken cloud (5–7 oktas) at 3,200 ft. Other codes: FEW (1–2 oktas), SCT (scattered, 3–4), OVC (overcast, 8). The lowest BKN or OVC layer is your ceiling, which matters for deciding whether you can fly visually.
6. Temperature and dew point
17/12 is temperature 17°C, dew point 12°C. The closer these two numbers are, the higher the humidity and the greater the risk of fog or low cloud forming. An M prefix means minus, e.g. M02/M05.
7. Pressure
Q1023 is the QNH — the pressure setting (1023 hPa) you dial into your altimeter so it reads height above sea level. American reports use an A prefix in inches of mercury, e.g. A2992.
Putting it together: flight categories
Controllers and briefing tools combine ceiling and visibility into a flight category: VFR (good), MVFR (marginal), IFR and LIFR (progressively worse). Our decoder colour-codes this automatically so you can judge conditions at a glance.
Frequently asked questions
How often is a METAR updated?
Usually every hour, with a SPECI (special report) issued in between when conditions change significantly.
What is the difference between a METAR and a TAF?
A METAR reports what the weather is doing now; a TAF forecasts what it will do over the next 24–30 hours. Read our guide to decoding TAFs next.
Want to go deeper on weather? Visit our Aviation Weather hub for more plain-English guides.