What do FEW, SCT, BKN, and OVC mean in a METAR?

They describe sky cover in oktas, or eighths of the sky. FEW is 1 to 2 oktas, SCT (scattered) is 3 to 4, BKN (broken) is 5 to 7, and OVC (overcast) is a full 8 oktas. BKN and OVC layers form a ceiling, the lowest layer that obscures more than half the sky.

What does CAVOK mean?

CAVOK stands for Ceiling And Visibility OK. It is reported when visibility is 10 km or more, there is no cloud below 5,000 feet or below the highest minimum sector altitude, and there is no significant weather. It is a shorthand for benign conditions.

How are weather phenomena built up in a METAR?

A weather group is read left to right as intensity, then descriptor, then phenomenon. A minus sign means light and a plus sign means heavy. So +SHRA is heavy rain showers, FZFG is freezing fog, and VCTS is a thunderstorm in the vicinity of the airfield.

What is the difference between BR and FG?

Both are reductions in visibility from suspended water droplets. BR is mist, reported when visibility is between 1,000 and 5,000 metres. FG is fog, reported when visibility drops below 1,000 metres. The threshold is purely the prevailing visibility.

Do TAF forecasts use the same codes as METAR?

Yes. A TAF (Terminal Aerodrome Forecast) uses the same sky cover, precipitation, and obscuration codes as a METAR observation. TAFs add change groups such as BECMG for a lasting change and TEMPO for short-lived fluctuations to describe how conditions will evolve.

METAR Abbreviation Reference

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Reading a METAR

A METAR is a coded aerodrome weather observation, and a TAF is its forecast cousin. Both pack sky cover, visibility, weather phenomena, and wind into terse abbreviations. This reference lists the common codes grouped by category — sky cover, intensity and proximity, descriptors, precipitation, obscurations, other phenomena, wind, and trend — and lets you filter by code or plain English.

How it works

Weather groups are not random letters; they follow a fixed order so they can be read mechanically:

[intensity][descriptor][phenomenon]
-          light          minus sign
+          heavy          plus sign
SH RA  ->  rain showers
FZ FG  ->  freezing fog
VC TS  ->  thunderstorm in the vicinity

Sky cover is reported in oktas (eighths): FEW, SCT, BKN, OVC, climbing from a couple of clouds to a fully overcast sky. A BKN or OVC layer counts as a ceiling. Wind adds G for gusts and KT for knots, e.g. 24018G30KT is wind from 240 degrees at 18 knots gusting 30.

Tips and notes

CAVOK collapses several good-weather conditions into one word, while NOSIG, BECMG, and TEMPO describe how conditions are expected to change. The RMK keyword introduces a remarks section that, in US reports, carries extra automated data after the main body.