消 'to dispel' + 暑 'summer heat' = 'to dispel the summer heat.' Pair with 消愁 (xiāochóu, 'dispel sorrow') and 消食 (xiāoshí, 'aid digestion') — 消 X is a productive 'get rid of X' frame.
culture
Classic 消暑 foods include 绿豆汤 (lǜdòu tāng, 'mung bean soup'), 西瓜 (xīguā, 'watermelon'), and 凉茶 (liángchá, 'cooling herbal tea').