Why You Sometimes See SPECI Instead of METAR

The first word of an observation tells you why it exists. A SPECI is a special observation issued off the hourly cycle when conditions change significantly, such as a sudden visibility or ceiling drop. A METAR, by contrast, is the routine report taken on a fixed schedule. Same station, same field order, same units: the only difference is the trigger, and that difference is itself a piece of weather information.

This guide explains what each report type means, why the leading word sometimes disappears, and how to use the report type as a signal. It is part of the METAR field guide.

METAR is the routine, scheduled observation

A METAR is the regular pulse of an airport's weather. It is taken on a fixed cycle, usually once an hour, and at many busy fields twice an hour. You can count on it arriving whether the weather is glassy calm or actively falling apart. That predictability is the point: pilots, dispatchers, and forecasters all know roughly when the next routine report is due.

Because it is scheduled, a METAR is a snapshot at a known time. The DDHHMMZ time group near the front tells you exactly when the observation was valid, in Zulu (UTC). If you are unsure how to read that group, see why METARs use Zulu time. The routine cadence also means that if nothing eventful happens, an hour can pass between updates, and the weather can drift within that hour.

SPECI is the special, unscheduled observation

A SPECI fills the gaps between the routine reports. It is issued when something changes enough to matter before the next scheduled METAR is due. Typical triggers include:

• A sudden wind shift.
• Visibility dropping (or recovering) across an operationally important threshold.
• A ceiling lowering across a threshold, for example the lowest broken or overcast layer dropping toward the floor of a flight category.
• A thunderstorm beginning or ending.

The common thread is a significant change, not a fixed clock. That is why a SPECI can land 12 minutes after a METAR, or 47 minutes after one. The system is telling you the previous picture is already out of date.

Operationally, the report type is a free interpretation hint. If a string of routine METARs is suddenly interrupted by a SPECI, the smart first question is "what just crossed a line." The thresholds that often trigger a SPECI are the same ones that move an airport between flight categories, so a SPECI frequently coincides with a VFR-to-MVFR or MVFR-to-IFR change.

The report type is the first word

Both report types put the type label at the very front, before the station id. The field order is identical from there on: station, time, optional AUTO or COR, wind, visibility, weather, clouds, temperature and dewpoint, pressure, then remarks.

METAR KDFW 291953Z 18012KT 10SM FEW250 31/19 A2998 RMK AO2
SPECI KDFW 292014Z 20018G29KT 4SM TSRA BKN035CB 26/21 A2995 RMK AO2

Read those two side by side and the story writes itself. The routine 1953Z METAR shows a benign afternoon: light wind, 10 statute miles of visibility, a high layer at 25,000 feet. Twenty-one minutes later the SPECI fired because a thunderstorm arrived: the wind jumped to 18 knots gusting 29, visibility collapsed to 4 statute miles in thunderstorm and rain, and a broken cumulonimbus deck appeared at 3,500 feet. Nothing scheduled that 2014Z report; the change did. For more on that gusting wind token, see reading the METAR wind group.

In the US the leading word is often omitted

Here is the wrinkle that trips up new readers. In the United States the leading METAR or SPECI word is frequently dropped from the transmitted text, so the report simply begins with the four-letter station id:

KDFW 291953Z 18012KT 10SM FEW250 31/19 A2998 RMK AO2

That is the same routine report as before, just without its type label. The data is unchanged, the field order is unchanged, and you decode it exactly the same way. So if you go looking for the word "METAR" at the front and find a station id like KDFW or KLAX instead, nothing is wrong: you are looking at a US-style observation with the report type stripped. When the word is present, it is doing one job: telling you whether the observation was scheduled or special.

Why the report type is worth a glance

The values in an observation tell you what the weather is. The report type tells you something subtler: whether the system thought the weather was changing fast enough to interrupt its own routine. A page full of METARs at neat hourly intervals suggests a stable airport. A METAR followed quickly by a SPECI suggests the opposite, and it is worth reading that SPECI carefully and checking the trend.

This is situational awareness, not an official briefing, so use the report type as one more clue rather than a verdict. When you paste a raw report into wxdecoder, the type label and every field are split out into labeled plain-English lines, so you can see at a glance whether you are reading the routine picture or the one that changed it.

Last updated June 29, 2026