unseasonable

From Middle English unseasonable, unsesonable, equivalent to un- +‎ seasonable.

unseasonable (comparative more unseasonable, superlative most unseasonable)

1. Not in accordance with the season.

   The snow in April was unseasonable.

   • 1838 (date written), L[etitia] E[lizabeth] L[andon], chapter V, in Lady Anne Granard; or, Keeping up Appearances. […], volume I, London: Henry Colburn, […], published 1842, →OCLC, page 44:

     There is a mania in every class to be mistaken for what it is not. Many things innocent, nay, even graceful in themselves, become injurious and awkward by unseasonable imitation.

• ill-timed, inopportune; see also Thesaurus:untimely

• seasonable

• unseasonableness
• unseasonably