Precipitation type definitions
Type set by size or state:
| Type | State / traits | Size (diameter) |
|---|---|---|
| Drizzle | Usually with fog or low stratus | Droplets under 0.02 in; bigger drops are rain |
| Freezing drizzle | Drizzle that freezes on contact | n/a |
| Virga | Rain that evaporates before hitting ground | n/a |
| Snow | Ice crystals; steady, or showers that start/stop fast | n/a |
| Snow grains | Drizzle-size equivalent of snow; white, opaque, fairly flat or elongated ice grains; do not bounce or shatter on hard ground (TP 10643) | Under 1 mm |
| Small hail | Hail (TC AIM MET 8.2) | Under 5 mm |
| Ice pellets | Transparent or translucent ice; spherical, irregular, or rarely conical; usually bounce and make sound on hard ground (TP 10643) | 5 mm or less |
| Hail | Small balls or pieces of ice (TP 10643; PHAK ch.12) | 5 mm to over 50 mm |
Trap: calling a small ice ball hail. Hail 5 mm to over 50 mm; ice pellets 5 mm or less.
References
- PHAK ch.12 Precipitation
- TP 10643 (When in Doubt... Small and Large Aircraft)