DictionaryautumnalRelating to autumn
adjective

autumnal

aw-TUM-nuhl/ɔːˈtʌmnəl/

Relating to or characteristic of autumn.

The woods glow with autumnal colors beneath a clear October sky.

A small deciduous tree with russet, gold, and orange foliage, a few leaves falling, and a loose carpet of fallen leaves beneath it visibly conveys autumnal qualities.
Etymology

The pieces mean “pertaining to autumn.” English first used the adjective for things maturing or blooming in that season, then more broadly for whatever belongs to or suggests autumn.

In context

Poetry Of Slow Life9:22
dark, moody, autumnal landscapes I loved so much. But I found myself unable to conjure up the same melancholic feelings. Instead, my sketchbook was filled with spring, with light and lush greenery.
Slow & Cozy Rainy Day in the English Countryside | Day In Life Of A Beginner Artist | Paint With Me

More examples

  • A cool autumnal breeze blew across the lake.
  • The poem has a quiet, autumnal mood.
  • An autumnal display of pumpkins filled the shop window.

Similar words

fall
Is the common American seasonal term when used before a noun.
late-season
Describes timing more generally and need not mean autumn.