Hot Summer in Japan—Vocabulary You Will Feel on Your Skin! 🌞

It’s that time of year again—Japan’s summer is here, in all its sticky, sunny, sweat-drenched glory.

If you’ve ever spent a summer in Japan, you know it’s no joke.

But whether you are soaking up the sun in Japan or studying Japanese from afar, this is the perfect time to expand your vocabulary with some very seasonal words that locals use.

In today’s newsletter, we will explore the hot topic of summer in Japan—and introduce you to vocabulary that not only deepens your language skills, but also helps you feel the language on a visceral level. Ready to sweat (linguistically)?

Vocabulary Spotlight: When “暑い” Just Isn’t Enough

"Hot" in Japanese is descriptive and nuanced. Let’s dive into five key words that describe different levels of summer heat:

🌤 夏日（なつび）

Definition: A summer day — specifically, any day where the temperature hits 25℃/77℉ or higher.

Think of this as your “entry-level” summer day. Warm, but manageable. You will hear weather reports mention 今日は全国的に夏日となるでしょう—“Today, it will be a summer day across the country.”

☀️ 真夏日（まなつび）

Definition: A midsummer day, with temperatures reaching 30℃/86℉ or more.

Now things are heating up. This is the kind of day when the cicadas are screaming, 扇風機 (electric fan) becomes your best friend, and 冷やし中華 (chilled ramen noodles) is back on the menu.

🔥 猛暑（もうしょ）

Definition: Extreme heat, officially 35℃/95℉ or more.

You will see this one in weather warnings. 猛 means “fierce,” and it’s no exaggeration. These are the days when even locals complain—and エアコン (air conditioning) becomes less of a luxury and more of a survival tool.

🫠 酷暑（こくしょ）

Definition: Severe heat—like 猛暑, but often used to describe the general intensity of a heatwave, not just the temperature.

酷 means “cruel” or “harsh,” so this term carries a strong emotional punch.

It’s used in expressions like 酷暑の候（こくしょのそうろう）, which you will see in formal summer letters or business emails—a poetic nod to the season’s severity.

🌙 熱帯夜（ねったいや）

Definition: A tropical night, when the temperature doesn’t fall below 25℃/77℉, even after sunset.

You know those nights when you toss and turn, sweating even with the window open? That’s a 熱帯夜. Great word to know when you are explaining why you are exhausted the next morning.

Why This Matters for Your Fluency

These aren’t just “weather words.” They’re part of how Japanese people talk about their lives—from casual chats to formal letters. Using them naturally shows that you are not just learning Japanese—you are living it!

✔︎ Next time you write a diary entry or send a message to a language partner, try describing the weather using one of these words.

✔︎ Listen for them in weather forecasts or news reports.

✔︎ And if you are in Japan? Drink lots of water. Wear a hat. And maybe keep a fan on hand—literal or language-learning.

Stay cool, both in temperature and in your studies! 😎