Precipitation Type in Middle and High Latitudes
(Nearly all precipitation starts out aloft as snow.  What reaches the surface depends on the
 temperature and humidity profiles and also the circulation pattern beneath the originating cloud.)
Atmospheric Conditions beneath Cloud (where precipitation originates as snow) Precipitation Type
Low humidity None (Fall Streaks, Virga)
Below freezing all the way or nearly all the way to the ground Snow
Warm, above freezing near the ground Rain
Warm, above freezing intermediate layer; thick subfreezing layer on ground Sleet
Warm, above freezing intermediate layer; thin subfreezing layer on ground Freezing rain
Warm near ground with strong convective updrafts and downdrafts Rain and/or Hail