March 21st, is The Fragrance Day™ according to The Fragrance Foundation which they established in 2018 for fragrance consumers.
The Fragrance Foundation officially established March 21st as The Fragrance Day™ in 2018. The goal is to drive awareness, excitement, and education around the fragrance category for consumers, unite the fragrance community, and kick-off the Spring season. From FiFi’s website.
Among other things, you can still celebrate the spring equinox i.e. the beginning of spring in the Northern Hemisphere and the beginning of fall in the Southern Hemisphere. This Day was set by the Sun itself.