METAR weather code reference for SG (Snow Grains)
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.
Here are common ways SG appears in real METAR observations:
SG-SGSG BRThese METAR codes are commonly seen alongside SG or describe related weather phenomena:
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.
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.