炎暑[ensho] heat wave
寒暑[kansho] hot and cold
劇暑[gekisho] severe heat
厳暑[gensho] extreme heat
向暑[kousho] facing the heat

酷暑[kokusho] intense heat
残暑[zansho] late summer heat
暑い[atsui] hot (weather, etc.)
暑がり[atsugari] (person) sensitive to heat
暑さ[atsusa] heat (of the weather)