METAR weather code reference for RA (Rain)
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).
Here are common ways RA appears in real METAR observations:
RA-RA+RA BRThese METAR codes are commonly seen alongside RA or describe related weather phenomena:
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.
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.
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.