快晴(かいせい)

かいせい
noun
clear weather, fine weather
See also: 改正(かいせい) (revision, amendment)
1. clear weather, cloudless sky
Weather condition with a completely clear, blue sky and no clouds.
今日(きょう)は快晴(かいせい)で気持(きも)ちがいい。
It's clear and beautiful weather today, which feels great.
運動会(うんどうかい)の日(ひ)は快晴(かいせい)だった。
The day of the sports festival was perfectly clear.
快晴(かいせい)の空(そら)の下(もと)でピクニックを楽(たの)しんだ。
We enjoyed a picnic under the clear blue sky.

快晴(かいせい) means perfectly clear, cloudless weather — stronger than just 晴(は)れ (sunny). In meteorological terms, it indicates cloud cover of 10% or less.

WORD FORMATION:
快(かい) (pleasant) + 晴(せい) (clear)

WEATHER VOCABULARY HIERARCHY:

  • 快晴(かいせい): perfectly clear, cloudless
  • 晴(は)れ: sunny, fine weather (may have some clouds)
  • 曇(くも)り: cloudy
  • 雨(あめ): rain

COMMON COLLOCATIONS:

  • 快晴(かいせい)の空(そら) (a cloudless sky)
  • 快晴(かいせい)に恵(めぐ)まれる (to be blessed with clear weather)

USAGE:
Often used to express satisfaction about good weather for events: 運動会(うんどうかい)の日(ひ)は快晴(かいせい)だった (the sports day was perfectly clear).

general
Added 2026.1.13 21:17 · Revised 2026.3.30 12:20
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