How to read a METAR
A METAR is the standard surface weather observation used at airports worldwide, issued every 30 or 60 minutes. It looks like line noise; it's actually a fixed sequence of elements. Here is a realistic example, decoded by this site's parser:
- Wind
- From 250° (WSW) at 12 kt, gusting 22 kt
- Visibility
- 10 km or more
- Weather
- Light rain, Rain
- Clouds
- Scattered at 1,800 ft; Broken at 3,500 ft
- Temperature
- 17°C (63°F), dewpoint 12°C (54°F)
- Pressure
- 1004 hPa (29.65 inHg)
METAR EGLL 031320Z — type, station, time
The report type (METAR — routine; SPECI marks an unscheduled special report), the station's 4-letter ICAO code (EGLL = London Heathrow), and the observation time: day of month 03, time 1320 UTC — METAR times are always UTC ("Z", zulu).
25012G22KT 220V280 — wind
First three digits: direction the wind blows from, in degrees true (250° ≈ west-southwest). Next digits: mean speed, then G22 — gusts to 22. Unit KT = knots (Russia/CIS uses MPS, metres per second). The optional 220V280 group says the direction varies between 220° and 280°. VRB replaces the direction when the wind is light and variable; 00000KT is calm.
9999 — visibility
Prevailing visibility in metres; 9999 is the code for 10 km or more. North American reports use statute miles instead (10SM, 1/2SM). If conditions are excellent, the whole visibility/weather/cloud block may be replaced by CAVOK — ceiling and visibility OK.
-RA — present weather
Weather phenomena are two-letter codes with an optional intensity prefix: - light, nothing = moderate, + heavy, VC in the vicinity. -RA is light rain. Codes combine: TSRA = thunderstorm with rain, FZFG = freezing fog. The glossary lists them all.
SCT018 BKN035 — clouds
Coverage in eighths (oktas): FEW 1–2, SCT scattered 3–4, BKN broken 5–7, OVC overcast 8. The three digits are the cloud base in hundreds of feet above the aerodrome — SCT018 = scattered at 1,800 ft, BKN035 = broken at 3,500 ft (that broken layer is the ceiling). Suffixes CB (cumulonimbus) and TCU (towering cumulus) flag convective clouds; VV003 means the sky is obscured with vertical visibility 300 ft.
17/12 — temperature / dewpoint
Both in whole degrees Celsius; M prefixes negative values (M02/M05 = −2°C / −5°C). A small temperature–dewpoint spread warns of fog or low cloud.
Q1004 — pressure
QNH — the altimeter setting — in whole hectopascals. North America reports inches of mercury instead: A2992 = 29.92 inHg (≈1013 hPa).
TEMPO 4000 RA — trend
Some countries append a two-hour trend: NOSIG — no significant change expected; BECMG — a lasting change is coming; TEMPO — temporary fluctuations, here visibility dropping to 4,000 m in moderate rain. Australia and Brazil also use INTER for shorter intermittent changes. Anything after RMK is remarks — station type, precise temperatures, sea-level pressure and more.
Missing data
Slashes mean "not available": //// for visibility, XX or MM in place of a temperature value (XX/12, 17/MM). Automated stations (AUTO) omit what their sensors can't see.