暑 （ショ） heat, midsummer

暑中見舞 （ショチュウミマイ） summer greeting card, inquiry after someone's health in the hot season

残暑 （ザンショ） late summer heat, lingering summer heat

避暑 （ヒショ） escaping the summer heat, going somewhere cooler during the summer, summering

暑い （あつい） hot, warm, sultry, heated, passionate, impassioned, burning (desire, etc.), on everybody's mind, on the radar, du jour, interested (gaze, etc.)

暑い盛り （あついさかり） heat of the day, hottest part of the day