What does 快晴 mean?
快晴 is a Japanese noun meaning “good weather” in English. It is written as 快晴 in kanji, かいせい in hiragana, and kaisei in romaji. This word is part of JLPT N2 vocabulary.
Example sentence
今日は快晴だ。これで一日中仕事が出来る。
It's fair today, so we can work all day.