Aviation Weather Abbreviations: Which Product Uses Which
Aviation weather abbreviations are not one vocabulary. They are six, and the most common source of confusion is expecting a code from one product to mean something in another.
This page maps which vocabulary belongs to which format, and where the overlaps genuinely are. For the full code lists, each section points at the page that holds them.
The six formats
Every product you meet in a briefing falls into one of six groups.
| Format | What it is | Vocabulary |
|---|---|---|
| METAR | surface observation | the largest shared code set |
| TAF | aerodrome forecast | METAR codes plus change groups |
| PIREP | pilot report | slash-tagged fields, hazard words |
| SIGMET and AIRMET | area hazard warnings | fixed hazard phrases |
| Winds aloft | upper wind forecast | positional digits, no letters |
| Military TAF | service aerodrome forecast | TAF codes plus numeric groups |
METAR and TAF share most of it
These two are the closest pair, and learning one gets you most of the other.
Wind, visibility, present weather and cloud use identical codes in both. BKN015
means a broken layer at 1500 feet whether it was observed or forecast.
A TAF adds the change groups that build a timeline: FM, TEMPO, BECMG,
PROB30 and PROB40. It also adds P6SM and NSW, which only make sense
about the future.
A METAR adds everything after RMK. Sea-level pressure, the temperature group,
precipitation amounts and the peak wind all record measurements, so a forecast
has no use for them.
The full lists are on the METAR abbreviations and TAF abbreviations pages.
PIREPs use tagged fields
A PIREP looks nothing like the first two, because it is built from tagged fields rather than a fixed sequence.
Each field opens with a slash and two letters. /OV is where. /FL is how
high. /TP is the aircraft. /TB is turbulence and /IC is ice.
Inside the hazard fields sits a vocabulary no other civil product uses. LGT,
MOD and SEV for intensity. OCNL and CONS for frequency. RIME, CLR
and MIXED for ice type, and CHOP, CAT and MWAVE for turbulence type.
An AIREP carries the same hazard words with the tags removed and the fields in fixed positions.
SIGMETs use fixed phrases
Area warnings use a short list of set phrases rather than compressed codes, because they are read under pressure.
SEV TURB is severe turbulence. SEV ICE is severe icing. EMBD TS is
embedded thunderstorms. VA CLD is a volcanic ash cloud. MOV E 20KT gives
movement, and INTSF, WKN and NC give the trend.
None of these appear in a METAR or a TAF. They exist only in the SIGMET and AIRMET family.
Winds aloft have no letters at all
An FB bulletin is the odd one out, and it defeats people who try to read it as codes.
There are no abbreviations. A group like 2434-04 carries wind direction, wind
speed and temperature packed into digits, and which altitude it applies to
depends on which column it sits in.
So layout matters more than vocabulary here. Flatten the spacing and the meaning is gone. That is why our decoder reads it from the raw text, not a tidied copy.
Military TAFs add numeric groups
A military TAF reads as a normal TAF until the trailer at the end.
There it adds three things a civil forecast never carries. A turbulence group
starting with 5, an icing group starting with 6, and an altimeter group written
as QNH2992INS.
The numeric hazard codes map onto the same meanings the PIREP words carry, so
severe rime icing is severe rime icing whether it arrived as MOD RIME in a
report or as a digit in a forecast group.
Service remarks such as AMD NOT SKED are the other addition, and they describe
the forecasting service rather than the weather.
Where codes cross between products
A few codes do travel, and knowing which ones saves a lot of second-guessing.
The hazard ladder is the big one. Trace, light, moderate and severe mean the same thing in a PIREP, in an AIRMET, in a SIGMET and in a military TAF group. Only the way they are written changes.
Ice types cross too. Rime, clear and mixed carry the same meaning whether they arrive as a word in a PIREP or as a digit in a forecast group.
Cloud codes cross between METARs and TAFs and nowhere else. BKN015 has no
meaning in a PIREP, which reports cloud in its own /SK field instead.
And the change groups belong to TAFs alone. TEMPO in a trend group on an
international METAR is the one exception.
Verdict on aviation weather abbreviations
Learn them by product rather than alphabetically, because a code only means something inside the format that owns it.
Start with METAR, which carries into TAF and covers most flying. Add PIREP fields next, since they are the only source for turbulence, icing and cloud tops. SIGMET phrases and the military groups come after, and winds aloft last, because it is the one format where there is nothing to memorise and everything depends on the column.
Frequently asked questions
How many aviation weather formats are there?
Six in common use: METARs, TAFs, PIREPs, SIGMETs and AIRMETs, winds aloft forecasts, and military TAFs. Each has its own vocabulary, though METARs and TAFs share most of theirs.
Do all aviation weather products use the same abbreviations?
No. METARs and TAFs share a body vocabulary. PIREPs use tagged fields with their own hazard words. SIGMETs use fixed hazard phrases. Winds aloft use a positional numeric format with no letters at all.
Which format has no letters?
Winds aloft. An FB bulletin is a column of four and six digit numbers, where the digits carry direction, speed and temperature together. Reading it depends on column position rather than on codes.
Where do PIREP abbreviations differ most?
PIREPs use slash-tagged fields such as OV for location and TB for turbulence, which no other product does. The hazard words inside those fields are shared with military TAF codes at the level of meaning.
Which product should I learn first?
METAR. Its vocabulary carries straight into TAFs, which together cover most day-to-day flying. PIREPs and SIGMETs add hazards the first two never mention, so they come next.