• 夏なつ — summer
• 夏休なつやすみ — summer vacation
• 真夏まなつ — midsummer
• 初夏しょか — early summer
• 夏服なつふく — summer clothes
• 夏祭なつまつり — summer festival

More examples ▼

• 夏季かき — summer season (formal)
• 夏期かき — summer term / summer period
• 夏至げし — summer solstice
• 常夏とこなつ — everlasting summer
• 冷夏れいか — cool summer
• 晩夏ばんか — late summer
• 夏草なつくさ — summer grass
• 春夏秋冬しゅんかしゅうとう — spring, summer, autumn, and winter / the four seasons

夏 originally showed a dancer wearing a mask for rituals — often performed during summer festivals. The symbol gradually became associated with the season of heat and festivities.