Types of precipitation

050-05-02Pablo Asensio Martínez2026-04-012 min

Rain and snow mixed Mixed precipitation: rain and snow (sleet) on a vehicle's windshield.

Precipitation is classified according to its character (continuity) and its physical form (type).

Classification by Character

The character of precipitation tells us the type of cloud it comes from:

Character Description Associated Cloud Type
Continuous Without interruptions for more than 60 min. Gradual intensity. Stratiform Clouds (Nimbostratus, Altostratus)
Intermittent Falls "from time to time", without marked breaks. Stratiform Clouds
Showers Short duration, abrupt start and stop. Clearings between precipitation. Cumuliform / Convective Clouds (Cu, Cb, TCU)

Types of Precipitation and Characteristics

Rain (RA)

  • Size: Droplets from 0.5 mm to 5.5 mm.
  • Visibility: Relatively good compared to snow (3 km - 5.5 km, or 1000 m in heavy rain).
  • Note: Droplets larger than 5.5 mm are unstable and break up.

Drizzle (DZ)

  • Size: Very small droplets, from 0.2 mm to 0.5 mm.
  • Origin: Low stratiform clouds (Stratus) or fog.
  • Visibility: Reduced (500 m - 3000 m). Imperceptible impact.

Snow (SN)

  • Visibility: Very poor. Snow reduces visibility much more than rain due to its open and opaque structure. Heavy snow can reduce visibility to almost 0 meters.
  • Snowflakes: Agglomeration of crystals (> 4 mm).

Hail (GR)

  • Size: > 5 mm.
  • Origin: Exclusively from Cumulonimbus (Cb).
  • Structure: Concentric layers of clear and opaque ice (like an onion).
  • Hazard: Severe damage to aircraft. Can be found at any height within or below a Cb.

Small Hail / Graupel (GS)

  • Size: < 5 mm.
  • Origin: Cb or TCU.
  • Appearance: Opaque balls of ice (snow that has collided with supercooled water).

Ice Pellets (PL)

  • Size: < 5 mm.
  • Appearance: Transparent or translucent pellets, spherical or irregular.
  • Behavior: Bounce when hitting the ground.
  • Formation: Indicate freezing rain aloft. Snow melts falling through a warm layer and refreezes passing through a lower cold layer before touching the ground.

Snow Grains

  • Size: < 1 mm.
  • Appearance: White and opaque grains, flat or elongated.
  • Origin: Stratus or fog.
  • Behavior: Do not bounce or break on impact. Frozen equivalent of drizzle.

Visibility Summary

  • Worst Visibility: Snow (especially "Blowing Snow" or heavy snow).
  • Best Visibility: Rain (for the same moisture content).
  • Visibility in heavy rain is better than in a snowstorm or blizzard.