the vernal [autumnal] equinoctial week (▼vernalは春の，autumnalは秋の)
I visit our family grave during the equinoctial week.
the spring [autumn] equinox
Extremes of temperature last only until the equinox.
彼岸会｜Buddhist services performed during the equinoctial week
彼岸桜｜a variety of cherry (tree) which blossoms around the time of the vernal equinox
彼岸花｜a cluster amaryllis