noun
unseasonable; out of season
Describes weather, clothing, or events that are not typical for the current season.
今日は時候外れの暖かさだ。
Today's warmth is unseasonable.
時候外れの雪に驚いた。
I was surprised by the unseasonable snow.
季節外れ is more common and refers to something out of its proper season in a broader sense, while 時候外れ specifically emphasizes the weather or climate of the season.
Compound of 時候 (seasonal weather) + 外れ (deviation). The exact historical derivation is uncertain, but the meaning is transparent from its components.