"consisting of or accompanied by sleet," 1725, from sleet (n.) + -y (2).
Entries linking to sleety
sleet n.
c. 1300, slete, "precipitation of mingled snow and rain," probably from an unrecorded Old English *slete, *slyte, which is perhaps related to Middle High German sloz, Middle Low German sloten (plural) "hail," from Proto-Germanic *slautjan- (source also of dialectal Norwegian slutr, Danish slud, Swedish sloud "sleet"), which is of uncertain etymology. In U.S. especially fine pellets of snow mingled with rain, usually wind-driven.
-y 2
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.