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middle of summer; height of summer; midsummer
真夏の太陽は厳しい。
The midsummer sun is harsh.
真夏でも朝は涼しいこの町が好きだ。
I like this town where mornings are cool even in midsummer.
真夏にスーツを着て歩くのはつらい。
Walking in a suit in midsummer is tough.