Translation

季節にふさわしい / 時宜を得た / 時期に合った

Meaning

Seasonable means suitable for the season, appropriate to the time, or timely. It is much less common than seasonal. The safest everyday use is seasonable weather: weather that feels normal or appropriate for that season.

Examples

• 今日はこの時期らしい涼しい天気です。
  We are having seasonable cool weather today.
• 彼女の助言は時宜を得たもので、混乱を防ぎました。
  Her seasonable advice prevented confusion.