Falling pellets (5)
I believe the answer is:
sleet
'falling pellets' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sleet that I've seen before include "Snowy rain" , "Precipitate evolution" , "Partly melted falling snow or hail" , "Partly frozen rain" , "Mixture of rain and snow" .)