An example
Here is a real-format report from New York JFK:
KJFK 241851Z 23009KT 10SM FEW070 BKN250 16/02 A3053 RMK AO2 SLP338 T01610022
Read left to right: JFK, on the 24th at 18:51 UTC, wind from 230 degrees at 9 knots, visibility 10 statute miles, a few clouds at 7,000 feet, broken clouds at 25,000 feet, temperature 16°C, dew point 2°C, altimeter 30.53 inches. The rest is remarks.
Group by group
| Group | Meaning |
|---|---|
| StationKJFK | The ICAO code of the airport. US codes start with K, Alaska PA, Hawaii PH. |
| Time241851Z | Day of the month and time in UTC (Z). The 24th at 18:51 UTC. |
| Wind23009KT | Direction the wind blows from, in degrees true, then speed in knots. 23009G18KT adds gusts to 18. VRB means variable, 00000KT calm. |
| Visibility10SM | Statute miles in the US. 10SM is the top of the scale. 1/2SM is half a mile. |
| Weather-TSRA BR | Precipitation and obscurations, if any. See the codes below. |
| CloudsFEW070 BKN250 | Cover and base in hundreds of feet above the field. FEW, SCT (scattered), BKN (broken), OVC (overcast). CLR or SKC means none. |
| Temperature16/02 | Temperature and dew point in °C. M means minus: M05 is -5°C. Close values mean fog is likely. |
| AltimeterA3053 | Pressure setting in inches of mercury: 30.53. Pilots set it so the altimeter reads field elevation. |
| RemarksRMK AO2 ... | Extra detail: AO2 is an automated station with a precipitation sensor, SLP is sea-level pressure, T is temperature to a tenth of a degree. |
The ceiling is the lowest broken or overcast layer. Few and scattered clouds do not count.
Weather codes
Intensity comes first: - light, nothing for moderate, + heavy. Then a descriptor and the phenomenon.
- RA rain, SN snow, DZ drizzle, GR hail, PL ice pellets.
- TS thunderstorm, SH showers, FZ freezing (FZRA is freezing rain).
- BR mist, FG fog, HZ haze, FU smoke.
- VC in the vicinity, not at the field: VCTS is a thunderstorm nearby.
So -TSRA is a thunderstorm with light rain, and +SN FG is heavy snow and fog.
Flight categories
Ceiling and visibility together give the flight category, which is what the colored dot on our airport pages shows.
| Category | Ceiling | Visibility |
|---|---|---|
| VFR | above 3,000 ft | more than 5 miles |
| MVFR | 1,000 to 3,000 ft | 3 to 5 miles |
| IFR | 500 to 999 ft | 1 to less than 3 miles |
| LIFR | below 500 ft | less than 1 mile |
The worse of the two decides. A 400 ft ceiling with 10 miles of visibility is still LIFR.
METAR vs TAF
A METAR is what the weather is now, issued every hour and more often when it changes (then called a SPECI). A TAF is the forecast for the next 24 to 30 hours, split into periods with FM (from), BECMG (becoming) and TEMPO (temporarily). Every airport weather page here shows both, decoded.
Weather in the Cockpit app
Every airport's METAR, TAF and ATIS decoded into plain words, with the raw text underneath.
