Stay Safe in Hiroshima’s Summer: What You Must Know About Heatstroke in Japan

☀ “Another hot summer has arrived” – but this is no ordinary heat

Every year on August 6, a memorial ceremony is held in Hiroshima Peace Memorial Park to remember the victims of the atomic bombing.
The mayor’s speech often begins with the words:

“Another hot summer has arrived.”

But the heat in modern-day Hiroshima is no longer just “hot” — it’s deadly.

🌡 Temperature Comparison

Even many Japanese people are hospitalized every summer from heatstroke — and they’re used to it.
For tourists unfamiliar with Japan’s humid climate, the risk is even greater.

🌡 What Makes Japanese Heat So Dangerous?

• Humidity: Often 70–90%. Your sweat doesn’t evaporate, so your body can’t cool itself.

• Concrete & asphalt: These surfaces absorb and radiate heat, making it feel even hotter.

• No breeze: Urban areas like Hiroshima often trap heat with little airflow.

• Nights stay hot: You might not cool down even after sunset.

It’s not just “hot” — it’s like walking in a giant sauna.

🔥 Common Mistakes by Tourists (especially from dry climates)

• “It’s not that hot” → Start walking long distances → Collapse from heatstroke

• “I’m not sweating much” → Danger! Sweat isn’t evaporating — heat is trapped in your body

• “Locals seem fine” → They’re avoiding sun, using umbrellas, resting indoors

Even Kyoto has seen foreign tourists hospitalized due to underestimating Japan’s heat.

🧃 Your Lifesaver: What is “OS-1”?

OS-1 is a special drink sold in Japanese drugstores and some convenience stores.
It’s a medical-grade oral rehydration solution, similar to an IV drip — but in a bottle.

体が知ってる大切な水と電解質。軽度から中等度の脱水症に経口補水液オーエスワンhttps://t.co/R7YstHj6oh

— オーエスワン［公式］ (@os1_official) July 31, 2023

Why it matters:

• Designed to treat dehydration and early heatstroke

• Quickly replaces fluids, salts, and sugar

• Approved for medical use in Japan

⚠️ Important: If OS-1 tastes “delicious,” it means your body is in danger.
Most people find it bland or salty. If it tastes good to you, you’re likely already dehydrated.

Always keep 1 bottle in your bag when exploring Hiroshima in summer.

🛒 Where to Buy OS-1 in Hiroshima

• Drugstores like Matsumoto Kiyoshi, Tsuruha, Welcia

• Some 7-Eleven or Lawson convenience stores

• Around Hiroshima Station and central shopping areas

You can ask:
🗣 “OS-1 wa arimasu ka?” (Do you have OS-1?)

☂ Pro Tips: Use a Sun Umbrella (yes, even men do!)

In Japan, many women use sun umbrellas in summer — but now, even men are doing it.
Black umbrellas are especially good at blocking heat.

They lower the temperature by 2–3°C and protect you from sunstroke.
Don’t be shy — locals will respect your smart choice.

🚶‍♂️ Use Underground Paths: Stay Cool in the “Shareo” Mall

Hiroshima has an underground mall called Shareo, which connects major areas like:

• Hiroshima Bus Center

• Hondori Shopping Street

• Peace Memorial Park (via walking)

Use this air-conditioned route to move around the city while avoiding the sun.

Kamiyacho Shareo

It opened in 2001 as Hiroshima's first underground shopping mall in Kamiyacho, the center of Hiroshima. It offers a wide...

dive-hiroshima.com

✅ Summary: Your Heatstroke Survival Checklist

💬 Final Message

Hiroshima is a city of peace and remembrance.
But to fully experience its message, you must protect your own life first.

“Peace begins with kindness — including kindness to your own body.”

Stay hydrated. Rest often. Respect the heat.
We hope your trip is safe, memorable, and meaningful.