LESSON NOTES · レッスンノート

N5How you sound · Sep 20, 2026

暑あつい, 熱あつい, 暖あたたかい, 温あたたかい: four temperature words, two of them homophones

暑あつい and 熱あつい are both あつい; 暖あたたかい and 温あたたかい are both あたたかい. In each pair, the first one is about the air around you and the second is about a thing you could touch. That single rule covers almost every case.

Spoken Japanese does not distinguish them at all, which is why this is a reading and writing problem rather than a listening one. The trouble arrives the moment you type, because your input method will offer you both and pick the wrong one if you let it.

The basics

暑あつい vs 熱あつい

暑あつい is hot weather, or the sensation of being hot because of the environment. 熱あつい is a hot object — coffee, a bath, a pan.

今日きょうは暑あついですね。 — It's hot today, isn't it. (polite — the weather) このコーヒーは熱あついです。 — This coffee is hot. (polite — an object)

The kanji tell you: 暑しょ contains 日にち, the sun. 熱ねつ contains the fire radical at the bottom. Sun for the weather, fire for the thing.

暖あたたかい vs 温あたたかい

The same split at a lower temperature. 暖あたたかい is warm air or a warm environment; 温あたたかい is a warm thing you could touch, including food and drink.

春はるは暖あたたかいです。 — Spring is warm. (polite — the season) 温あたたかいスープが飲のみたい。 — I want some warm soup. (casual — an object)

温あたたかい also extends to people and feelings: 温あたたかい言葉ことば, "kind words", 温あたたかい人ひと, "a warm person". 暖あたたかい cannot do this, because air has no personality.

寒さむい vs 冷つめたい — the cold side works the same way

The cold pair is easier because the readings are different, but the same logic applies.

今日きょうは寒さむいです。 — It's cold today. (polite — the air) 手てが冷つめたい。 — My hands are cold. (casual — a thing)

寒さむい is the environment, 冷つめたい is an object. And 冷つめたい, like 温あたたかい, extends to people: 冷つめたい人ひと is a cold-hearted person. The full weather set is in Japanese weather vocabulary.

Beyond the basics

Your own body is an object

This is the exception that catches people. If a part of you is hot or cold, it is a thing, not an environment.

頭あたまが熱あつい。 — My head feels hot. (casual — possibly a fever) 足あしが冷つめたい。 — My feet are cold. (casual)

But if you as a whole are hot because the room is hot, that is 暑あつい: 暑あついから窓まどを開ひらけよう. Whole person in an environment takes the environment word; a body part takes the object word.

The figurative 熱あつい

熱あつい is the one with emotional range: passionate, intense, heated.

熱あつい試合しあいだった。 — It was an intense match. (casual) 熱あつい人ひと — a passionate person (casual, positive)

暑あつい cannot be used this way. A 熱あつい人ひと is fired up; an 暑あつい人ひと is just someone who is too warm.

Why your keyboard will get it wrong

Typing あつい gives you a list, and the conversion picks whichever candidate it used last. This means the most common written error is not a knowledge error at all — it is a conversion the writer did not check.

The fix is a habit: when you type あつい or あたたかい, look at what came out before you send it. Air or object. This is the same problem that makes 変換へんかんミス a recognised category of Japanese typo, and it is why native speakers make these errors too.

あったかい and あっつい

In casual speech both words get a small っ inserted for emphasis.

あったかい! — Ooh, warm! (casual — holding a hot drink) あっつ! — Ow, hot! (casual — an exclamation, often cut short)

These are not misspellings; they are spoken emphasis, written as heard. あっつ on its own, cut off before the い, is the standard reaction to touching something too hot.

Which one for a bath?

お風呂ふろ is 熱あつい when it is too hot to get into, and 温あたたかい when it is pleasantly warm. Both appear on the same evening. The bath is unambiguously an object, so 暑あつい never applies to it — a common learner error, and one that reads as a category mistake rather than a spelling slip.

All four words are い-adjectives, so they change form the same way (暑あつかった, 温あたたかくない). If that pattern is new, see い-adjectives vs な-adjectives.

Common mistakes

  • Using 暑あつい for coffee. Coffee is a thing: 熱あついコーヒー. 暑あついコーヒー suggests the coffee is experiencing summer.
  • Using 温あたたかい for the weather. Warm weather is 暖あたたかい. 温あたたかい天気てんき sounds like the weather is a bowl of soup.
  • Saying 暑あつい about your hands. A body part is an object: 手てが熱あつい.
  • Trusting the kanji conversion. Check what came out. This is where most written errors happen.
  • Using 暑あつい figuratively. Passion is 熱あつい. 暑あつい試合しあい would be a match played in hot weather.

The four-way table

Word Reading Applies to Example
暑あつい あつい Weather, environment 今日きょうは暑あつい
熱あつい あつい Objects; passion 熱あついコーヒー, 熱あつい試合しあい
暖あたたかい あたたかい Weather, environment 暖あたたかい春はる
温あたたかい あたたかい Objects; people, feelings 温あたたかいスープ, 温あたたかい人ひと
寒さむい さむい Weather, environment 今日きょうは寒さむい
冷つめたい つめたい Objects; cold-hearted people 冷つめたい水みず, 冷つめたい人ひと

FAQ

Do Japanese people ever mix these up? In writing, yes — the kanji conversion does it for them, and 変換へんかんミス of exactly this kind is common enough to be a running joke.

Which one do I use for a hot spring? 温泉おんせん itself is a place, but the water is an object: お湯ゆが熱あつい if it is too hot to enter.

Is 暖あたたかい ever used for objects? For clothing and bedding it does appear — 暖あたたかいコート — because the coat's job is to make the air around you warm. This is the main crossover case.

How do I say "warm-hearted"? 温あたたかい人ひと or 心こころが温あたたかい. 暖あたたかい人ひと is not used, because 暖だん belongs to the air.

What is the difference between 冷つめたい and 涼すずしい? 涼すずしい is pleasantly cool air — a nice breeze. 冷つめたい is a cold object. 涼すずしい is positive; 寒さむい is the uncomfortable version of the same environment.

Does this matter if I only speak? Less, since the readings are identical. It matters the moment you type or read, which for most learners is daily.

Practice

Build each answer before opening it. Questions 1 and 2 are a pair — same reading, different kanji.

1. Say "it's hot today."

Show answer

今日きょうは暑あついですね — 暑しょ contains 日にち, the sun. Weather. This is the pair to question 2.

2. Say "this coffee is hot."

Show answer

このコーヒーは熱あついです — 熱ねつ has the fire radical. An object. This is the pair to question 1.

3. Say "spring is warm."

Show answer

春はるは暖あたたかいです — the environment takes 暖だん.

4. Say "I want some warm soup."

Show answer

温あたたかいスープが飲のみたい — food is an object, so 温おん.

5. Something is wrong here: 暑あついコーヒーを飲のみました。

Show answer

熱あついコーヒーを飲のみました — 暑あつい would suggest the coffee is experiencing hot weather.

6. Say "my hands are cold."

Show answer

手てが冷つめたい — a body part is an object. 寒さむい is for the environment.

7. Say "it was an intense match."

Show answer

熱あつい試合しあいだった — only 熱あつい has the figurative, passionate meaning.

8. Describe someone as warm-hearted.

Show answer

温あたたかい人ひと — 暖あたたかい belongs to air and cannot describe a person.

9. You are hot because the room is hot. Which word?

Show answer

暑あつい — a whole person in an environment takes the environment word. A body part would take 熱あつい.

10. You touch a pan and pull your hand back. What do you say?

Show answer

あっつ! — the emphatic spoken form of 熱あつい, usually cut off before the い.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

暑い	あつい — hot (weather)
熱い	あつい — hot (object); passionate
暖かい	あたたかい — warm (weather)
温かい	あたたかい — warm (object, person)
寒い	さむい — cold (weather)
冷たい	つめたい — cold (object, person)
涼しい	すずしい — pleasantly cool
春	はる — spring
天気	てんき — weather
風呂	ふろ — bath
湯	ゆ — hot water
手	て — hand
足	あし — foot, leg
試合	しあい — match, game
言葉	ことば — words
飲む	のむ — to drink

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime. Air or object is the only rule you need here, and it has held up for every student I have given it to — including for the bath, which is the case people always ask about next.

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Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N5

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