Definition of unseasonably in US English:

unseasonably

adverb

  • In a way that is unusual for the time of year.

    ‘unseasonably warm weather’
    • ‘The unseasonably dry winter has fire officials preparing for another busy summer.’
    • ‘Memories of previous heatwaves at exam time were washed away with the unseasonably heavy rain which has hit the country for most of June.’
    • ‘The water, 300 feet below, was unseasonably glassy, which made it hard to separate aircraft from watercraft.’
    • ‘A pest control expert has warned that the city centre is facing a "rats epidemic" following the unseasonably mild autumn.’
    • ‘Two thousand spectators braved the unseasonably brisk night to experience the spectacular demonstration of martial pride.’

Pronunciation

unseasonably

/ˌənˈsiz(ə)nəbli//ˌənˈsēz(ə)nəblē/