Meaning
暑 means hot — specifically the heat of the world around you. Sweltering summer sun, muggy afternoons, the breathless stillness of a Japanese August. That atmospheric, ambient heat is what this kanji captures.
Don't confuse it with 熱い (atsui). Both share the same pronunciation, but they describe different kinds of heat. 暑 is about weather and environment: the air, the season, the outdoors. 熱い is about objects and surfaces — boiling water, a hot bowl of ramen, a fever. The two contexts don't overlap in natural speech.
Look at the structure: 日 (sun) sits on top, and 者 (person) below. A blazing sun bearing down on a person — that image is 暑. Grade 3 kanji, 12 strokes, radical 日. The sun radical appears in many weather-related kanji, and 暑 fits squarely in that group.
For Vietnamese learners, the Hán-Việt reading is THỬ (暑), found in classical compounds like hàn thử (寒暑, cold and heat) and thử khí (hot air). For Chinese learners, the character is identical to Mandarin 暑 (shǔ) — the same one in 暑假 (shǔjià, summer vacation). You already know this one.
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi is ショ (SHO). You won't say it in casual conversation — it shows up in formal and seasonal compounds. These are the ones worth knowing:
- 暑中 (shochū) — midsummer; the hottest stretch of the year, roughly July 20 to August 6
- 酷暑 (kokusho) — intense heat, a brutal summer day
- 避暑 (hisho) — escaping the summer heat; heading somewhere cooler
- 寒暑 (kansho) — cold and heat; the full swing of seasonal temperatures
The ショ reading connects directly to Mandarin shǔ and Hán-Việt THỬ — a shared CJK root that makes it easier to retain.
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi is あつ.い (atsu.i). This is what you'll actually say every day. The dot marks the boundary between the stem あつ and the adjective ending い. Come July, atsui! will feel like your most-used word in Japanese.
- 暑い (atsui) — hot (weather); standard i-adjective
- 暑さ (atsusa) — the heat; noun form
- 暑がる (atsugaru) — to feel (or act) hot; used when describing someone else's reaction
The rule: if you're talking about the weather or the season, use 暑い. If you're warning someone their tea is scalding, use 熱い.
Common Words & Compounds
The most useful words built with 暑, grouped by use:
Everyday weather expressions
- 暑い (atsui) — hot (weather)
- 暑さ (atsusa) — the heat
- 蒸し暑い (mushiatsui) — hot and humid, muggy
- 暑がり (atsugari) — a person who feels the heat easily
Seasonal & formal terms
- 暑中 (shochū) — midsummer (roughly July 20 – August 6)
- 暑中見舞い (shochū mimai) — a summer greeting card sent during the hottest weeks
- 酷暑 (kokusho) — extreme heat, scorching weather
- 避暑 (hisho) — going somewhere cooler to escape the heat
- 避暑地 (hishochi) — a summer resort or cool getaway
Contrasting pairs
- 寒暑 (kansho) — cold and heat; seasonal extremes
- 寒い・暑い (samui / atsui) — cold / hot; the everyday weather pair
Body & feeling
- 暑がる (atsugaru) — to act like it's too hot (third-person expression)
- 残暑 (zansho) — lingering summer heat after the season should have cooled down
Example Sentences
きょうは本当に暑いですね。
Kyou wa hontou ni atsui desu ne.
It's really hot today, isn't it?
夏の暑さが苦手です。
Natsu no atsusa ga nigate desu.
I can't handle summer heat well.
昨日は蒸し暑くて、眠れませんでした。
Kinō wa mushiatsukute, nemuremasen deshita.
Yesterday was so muggy I couldn't sleep.
暑い日は、アイスクリームが食べたくなります。
Atsui hi wa, aisu kurīmu ga tabetaku narimasu.
On hot days, ice cream starts sounding very good.
彼は暑がりなので、いつもエアコンをつけています。
Kare wa atsugari na node, itsumo eakon wo tsukete imasu.
He's sensitive to heat, so the air conditioner is always running.
暑中見舞いを送りましたか？
Shochū mimai wo okurimashita ka?
Did you send a midsummer greeting card?
暑くて外に出たくありません。
Atsukute soto ni detaku arimasen.
It's so hot I don't want to go outside.
この夏は特に酷暑だと天気予報が言っていました。
Kono natsu wa toku ni kokusho da to tenkiyohō ga itte imashita.
The weather forecast said this summer would be especially brutal.
残暑がまだ続いているので、水分を取ることが大切です。
Zansho ga mada tsuzuite iru node, suibun wo toru koto ga taisetsu desu.
The lingering summer heat hasn't let up — staying hydrated is essential.
Related Kanji
- 寒 — Cold, Chilly, Winter (Kanji N4)
- 集 — Gather, Collect, Assemble (Kanji N4)
- 赤 — Red (Kanji N4)
- 風 — Wind, Style, Manner (Kanji N4)
- 重 — Heavy, Important, Layers (Kanji N4)
- 夜 — Night, Evening (Kanji N4)
Memory Tip
The structure of 暑 tells the story directly: 日 (sun) on top, 者 (person) below. Picture that person sweating, fanning themselves, desperate for shade. The sun is beating down. That scene is 暑.
This image also separates it from 熱. Same reading, different kanji, different situations. 暑 = the world around you is hot. 熱 = this specific thing is hot. One kanji, one scene — keep them separate and you'll stop second-guessing which to write.
Vietnamese speakers have a built-in hook: THỬ sounds like thử (to try/test). Imagine testing the weather by stepping outside barefoot. Immediate regret. That's your anchor for 暑.