METAR Weather Codes Reference

Liquid precipitation in the form of water droplets greater than 0.5 mm in diameter. Rain is the most commonly reported precipitation type in METARs and can be combined with intensity modifiers (- for light, + for heavy) and descriptors like SH (showers) or FZ (freezing).

Frozen precipitation in the form of ice crystals, most often occurring as snowflakes. Snow significantly reduces visibility and is a primary concern for aircraft icing, runway contamination, and braking action. Often reported with intensity modifiers.

Very fine, uniformly dispersed liquid precipitation with droplets smaller than 0.5 mm in diameter. Drizzle typically falls from stratus clouds and indicates stable atmospheric conditions with low ceilings. Freezing drizzle (FZDZ) is especially hazardous for aircraft.

Ice precipitation consisting of balls or irregular lumps of ice with a diameter of 5 mm (about 1/4 inch) or greater. Hail is associated with strong thunderstorms and poses a severe hazard to aircraft, capable of causing structural damage to airframes, windshields, and engines.

Small hail (graupel) or snow pellets less than 5 mm in diameter. These ice pellets form when supercooled water droplets freeze onto snowflakes. Less damaging than full hail but still indicates convective activity and potential for icing conditions.

Also known as diamond dust, ice crystals are tiny, unbranched ice particles that fall from a clear or nearly clear sky. They are most common at very cold temperatures (below -30C) and can create optical phenomena like sun dogs and halos. Often observed at high-altitude airports in arctic regions.

Small, translucent balls of ice that bounce when hitting the ground. Ice pellets (sleet) form when snowflakes melt in a warm layer aloft and then refreeze in a cold layer near the surface. Their presence indicates a complex temperature profile and often means freezing rain may be nearby.

Very small, white, opaque grains of ice that are essentially the frozen equivalent of drizzle. Snow grains are flat or elongated, usually less than 1 mm in diameter, and fall in small quantities from stratus clouds. They rarely reduce visibility significantly.

Used by automated weather stations when precipitation is detected by sensors but the type cannot be determined. This typically occurs when the station lacks the sensors needed to differentiate between rain, snow, or other precipitation types. Pilots should use caution and seek additional weather information.

Microscopic water droplets or wet hygroscopic particles suspended in the atmosphere, reducing visibility to between 5/8 of a mile and 6 miles. The abbreviation comes from the French word 'brume.' Affectionately known among pilots as 'baby rain,' BR is one of the most frequently reported obscurations and often accompanies low ceilings and stable air.

A visible aggregate of microscopic water droplets suspended at the earth's surface that reduces visibility to less than 5/8 of a statute mile. Fog is one of the most common causes of IFR conditions and flight delays. When visibility improves above 5/8 mile, the observation changes from FG to BR (mist).

Fine dry particles of dust, salt, or other matter suspended in the atmosphere that give the sky a characteristic opalescent appearance. Unlike mist, haze particles are not water-based. Haze reduces visibility and is most common in warm, dry conditions. It can persist for days under stagnant high pressure systems.

Small particles suspended in the air from combustion, such as wildfires, industrial activity, or agricultural burning. Smoke can dramatically reduce visibility across large areas and may persist for weeks during wildfire season. It can reach very high altitudes and affect flight operations far from the source.

Fine particles of earth or other matter raised from the ground by wind and suspended in the atmosphere. Widespread dust reduces visibility and is most commonly reported in arid regions. Dust events can cause significant restrictions to visibility and affect engine performance.

Larger particles of sand raised by the wind to moderate heights, reducing visibility. Sand is coarser than dust and typically stays closer to the surface. Blowing sand can cause engine damage, windshield abrasion, and significant visibility restrictions at airports in desert regions.

Fine particles of rock and glass ejected from a volcanic eruption and carried by wind. Volcanic ash is an extreme hazard to aviation because it can cause engine failure, erode windshields, clog pitot tubes, and contaminate aircraft systems. Pilots must avoid volcanic ash at all costs.

Water droplets torn from the surface of a body of water by strong winds and carried into the atmosphere. Spray is typically reported at coastal stations or near large bodies of water during high-wind events. It can reduce visibility near the surface.

A convective storm producing lightning and thunder. In METAR reports, TS indicates that thunder has been heard at the station within the observation period. Thunderstorms are among the most dangerous weather phenomena for aviation, bringing turbulence, wind shear, hail, heavy rain, and microbursts.

A sudden increase in wind speed of at least 16 knots, the speed rising to 22 knots or more and lasting for at least one minute. Squalls are associated with thunderstorms and frontal passages. They can cause rapid changes in wind direction and speed, creating hazardous crosswind conditions for landing and takeoff.

A rotating column of air. When reported as FC it indicates a funnel cloud (not touching the ground) or waterspout. When reported as +FC, it indicates a tornado or waterspout. This is one of the most urgent weather reports in aviation, demanding immediate avoidance.

A severe weather condition in which strong winds lift large quantities of dust into the atmosphere, reducing visibility to less than 5/8 of a mile. Dust storms can develop rapidly and create near-zero visibility conditions. They are most common in arid and semi-arid regions.

Similar to a dust storm but involving heavier sand particles. Sandstorms reduce visibility below 5/8 of a mile and are prevalent in desert regions. The larger particles tend to stay closer to the surface but can cause serious damage to aircraft surfaces and engines.

Well-developed rotating columns of dust or sand (dust devils) observed near the station. They are caused by intense surface heating and are typically small and short-lived, but can occasionally reach heights of several thousand feet. They can momentarily reduce visibility and cause turbulence near the surface.

Indicates that the sky is completely clear with no clouds at any altitude. SKC is used when a human observer reports clear skies. This represents 0/8 cloud coverage. A sky clear report means excellent VFR conditions with respect to cloud cover.

Used exclusively by automated stations (ASOS/AWOS) to indicate that no clouds were detected below 12,000 feet AGL. The sensor cannot detect clouds above that altitude, so CLR does not guarantee clear skies above 12,000 feet. Pilots planning flights above 12,000 feet should consult additional weather sources.

Cloud coverage of 1/8 to 2/8 of the sky. Few clouds indicate mostly clear conditions and are not considered a ceiling. Followed by a three-digit height in hundreds of feet AGL (e.g., FEW050 means few clouds at 5,000 feet). FEW conditions are VFR-friendly and pose minimal obstruction.

Cloud coverage of 3/8 to 4/8 of the sky. Scattered clouds are not considered a ceiling since more than half the sky is still visible. The three-digit number following indicates cloud base height in hundreds of feet AGL. Scattered layers still permit VFR operations under most circumstances.

Cloud coverage of 5/8 to 7/8 of the sky. A broken layer constitutes a ceiling because more than half the sky is obscured. The reported height becomes the ceiling height. BKN conditions often result in IFR or MVFR flight categories depending on the height of the cloud base.

Complete cloud coverage of 8/8 of the sky. An overcast layer is always a ceiling. The height reported is the ceiling height in hundreds of feet AGL. Low overcast layers (e.g., OVC005) represent IFR conditions and may require instrument approaches for landing.

Reported when the sky is completely obscured (typically by fog, heavy precipitation, or blowing snow) and individual cloud layers cannot be identified. The number following VV indicates how far upward the observer or sensor can see, in hundreds of feet. VV represents an indefinite ceiling and always indicates IFR conditions.

Placed before a weather phenomenon to indicate heavy intensity. For precipitation, heavy means the rate of fall is high and visibility is significantly reduced. For example, +RA means heavy rain and +SN means heavy snow. Heavy precipitation increases risks of reduced visibility, hydroplaning, and windshield obscuration.

Placed before a weather phenomenon to indicate light intensity. Light precipitation falls at a low rate and generally causes only minor reductions in visibility. For example, -RA means light rain and -SN means light snow. When no intensity modifier is present, moderate intensity is implied.

Indicates that the weather phenomenon is occurring in the vicinity of the airport, generally between 5 and 10 statute miles from the station, but not at the airport itself. Common examples include VCTS (thunderstorm in the vicinity) and VCSH (showers in the vicinity). Vicinity weather may move toward the airport and warrants monitoring.

Indicates a weather phenomenon that extends only a short distance above the surface, generally less than 6 feet deep. Most commonly used with fog (MIFG) to describe shallow fog that obscures the runway surface but allows visibility above the fog layer. Shallow fog can make taxiing hazardous while flight visibility may be adequate.

Describes a weather phenomenon occurring in irregular patches across the observation area rather than uniformly. Most commonly seen as BCFG (patches of fog), meaning fog covers some areas of the airport but not others. Patchy conditions can create unpredictable visibility changes during taxi, takeoff, and landing.

Indicates that the weather phenomenon covers a significant portion of the airport but not all of it. PRFG (partial fog) means fog obscures part of the airport, such as one end of the runway, while other areas remain clear. This can create significant challenges for approach and landing operations.

Low drifting phenomenon that stays below eye level (generally below 6 feet). Commonly paired with snow (DRSN), dust (DRDU), or sand (DRSA). Drifting indicates the particles are being carried along the surface by wind but are not raised to significant heights. It differs from blowing (BL), which extends above eye level.

Weather phenomenon raised by the wind to heights of 6 feet or more above the surface, significantly reducing visibility. Commonly used with snow (BLSN), dust (BLDU), and sand (BLSA). Blowing snow is especially hazardous because it can create whiteout conditions and make it impossible to distinguish the horizon or runway edges.

Precipitation characterized by sudden beginning and ending, and rapid changes in intensity. Showers fall from cumuliform (convective) clouds and tend to be brief but can be intense. Shower-type precipitation often includes intermittent heavy bursts separated by lighter periods. Common combinations include SHRA (rain showers) and SHSN (snow showers).

Indicates that liquid precipitation is freezing upon contact with surfaces at or below 0 degrees Celsius. Freezing rain (FZRA) and freezing drizzle (FZDZ) are among the most dangerous weather conditions for aircraft, causing rapid ice accumulation on wings, control surfaces, and engine inlets. Freezing fog (FZFG) deposits rime ice on exposed surfaces.

When used as a descriptor prefix, TS combines with a precipitation type to indicate that the precipitation is occurring with a thunderstorm. For example, TSRA means thunderstorm with rain, TSSN means thunderstorm with snow, and TSGR means thunderstorm with hail. Thunderstorm-associated precipitation is typically heavy and accompanied by turbulence and wind shear.