vensa -ves- gismu

x1 is spring/springtime [warming season] of year x2 at location x3; (adjective:) x1 is vernal.

See also citsi, crisa, critu, dunra.

In notes:

citsi
x1 is a season/is seasonal [cyclical interval], defined by interval/property x2, of year(s) x3.
crisa
x1 is summer/summertime [hot season] of year x2 at location x3.
critu
x1 is autumn/fall [harvest/cooling season] of year x2 at location x3.
dunra
x1 is winter/wintertime [cold season] of year x2 at location x3.