vernal adj.

"pertaining to spring," 1530s, from Late Latin vernalis "of the spring," from vernus "of spring," from Latin ver "the spring, spring-time," from PIE *wesr- "the spring" (source also of Old Norse var "spring," Greek ear, Armenian gar-un, Sanskrit vasantah, Persian bahar, Old Church Slavonic vesna "spring," Lithuanian vasara "summer").