noun
heat (of the weather); hotness
Refers specifically to atmospheric heat, the sensation of hot weather, or the degree of hotness. Often used in expressions like 暑さに弱い (sensitive to heat) or 暑さが厳しい (the heat is intense).
今年の夏は暑さが厳しい。
The heat is intense this summer.
彼は暑さに弱いので、夏はいつもぐったりしている。
He is sensitive to heat, so he always feels listless in summer.