vespertine

vespertine \VES-per-tin\, adjective:

1. Of, pertaining to, or occurring in the evening.
2. Botany. Opening or expanding in the evening, as certain flowers.
3. Zoology. Becoming active in the evening, as bats and owls.

To my own ear, I sound hyperpoetic, and I don't mean to exaggerate these vespertine moods; I think that this restlessness that I am describing was really quite ordinary.
-- Peter Gadol, The Long Rain

So on we journey'd, through the evening sky / Gazing intent, far onward as our eyes, / With level view, could stretch against the bright / Vespertine ray: and lo ! by slow degrees / Gathering, a fog made towards us, dark as night.
-- Dante Alighieri, The vision, or, Hell, Purgatory, and Paradise

Vespertine derives from Latin vespertīnus, "evening."