今年初の都心30℃超 5月なのに真夏日地点も最多 “寒暖差熱中症”警戒 患者急増(2026年5月17日)

In central Tokyo, temperatures exceeded 30°C for the first time this year, marking a true summer day. Clinics in Tokyo have already seen a sharp increase in heatstroke patients, more than double the number from the previous week. ■Once a year! A massive dam release in northern Kanto A tremendous volume of water cascaded out with a roaring sound. A mist rose, enveloping the surroundings. At the Yagisawa Dam, one of Kanto's major water reservoirs, the annual "inspection release" took place. Today, the 17th, was the hottest day of the year in Kiryu City, Gunma Prefecture. Approximately 1600 people visited, seeking a moment of coolness. (Participant from Chiba) "I want to get completely soaked!" (Participant from Tokyo) "With this heat, I wonder if I'll dry off (even if I get wet)." For some reason, some people were lying down and gazing at the sky... (Dam fan) "This is a way of expressing love for the dam, I guess. When you look straight up like this, you can really see the arch structure." (Director Tomohiro Kaneko) "40 minutes have passed since the water was released. The water volume is gradually increasing, and it's becoming impossible to see anything." The 'inspection discharge' releases up to 30 tons of water per second. The unexpected volume of water caused great confusion among the participants. "Aaaahhh!!!" Q. Are your glasses already...? "They're soaked. But I'm fine." "I don't have a change of clothes to take home, so I'm wondering what to do." "We're the worst." ■Central Tokyo over 30℃, record high for summer days nationwide The Japanese archipelago experienced summer-like heat, skipping over early summer. On the 17th, a record 200 locations nationwide recorded temperatures above 30°C, marking a midsummer day. Including those with temperatures above 25°C, almost the entire archipelago, excluding Hokkaido, would be colored red (indicating a summer day). The highest temperature recorded nationwide was in Kake, Akiota-cho, Hiroshima Prefecture, at 34.8°C. Local residents reacted to the near-extreme heat with comments: Q. I hear it's the hottest day in the country. (Local man) "Seriously?! Again? It's the hottest day in the country?" Q. 34.8°C today. "Seriously?!" In Gifu City, where a stone-skipping competition was held on the Nagara River, a high of 31.2°C was recorded, marking the first midsummer day of the year. ■ Sharp increase in heatstroke cases: "Handling hot iron with bare hands..." Some places are crying out in agony due to the unseasonable heat… (Announcer Kazuki Kusanagi) "Currently, forging work is being done in this workshop, and the heat is incredible when you get close." This cutlery workshop also handles custom orders. An essential element is the flame, which can reach 1200℃. The temperature in the workshop is 41℃. Furthermore… (Norifumi Yoshizawa (42), Yoshizawa Cutlery) "Since the fire is directly in front of us, I think it feels like it's about 10°C hotter." Looking at it with a thermal camera… "The craftsman's body is bright red. You can see that it's extremely hot. It's rising to nearly 60°C." He also takes measures to cope with the heat… (Norifumi Yoshizawa (42), Yoshizawa Cutlery) "I cool myself down with a spot cooler. If I direct too much of the cool air towards me, the iron that I've just heated will cool down, so I adjust it so that it only hits me as much as possible." He drinks 6 liters of water a day to prevent dehydration, but he says he has suffered from symptoms of heatstroke before. (Noriyuki Yoshizawa (42), Yoshizawa Cutlery) "I was so exhausted I could barely stand, and my thought process was probably malfunctioning. I tried to pick up the hot iron with my bare hands. It was terrifying. The heat is really something." ■Patients Double…Beware of "Temperature Difference Heatstroke" A clinic in Tokyo has already seen more than double the number of heatstroke patients in the past week. (Heatstroke patient (80s)) "I've had a headache that started in my shoulder…it's like a migraine." "Can I see your mouth and lips? Your lips are very dry, you're dehydrated." In the week leading up to the 10th of this month, 454 people nationwide were taken to the emergency room due to heatstroke. This is more than a 70% increase compared to last year. Heatstroke at this time of year also has certain characteristics. (Dr. Hiromichi Ito, Director of Ito Oji Kamiya Internal Medicine and Surgery Clinic) "It might be that the body is overheating. The body's temperature regulation function, such as sweating or increasing blood flow to the skin's surface to release heat, may not be keeping up with this heat. This is likely 'temperature difference heatstroke'." "Temperature difference heatstroke." The autonomic nervous system, which regulates body temperature, becomes fatigued by temperature fluctuations, leading to a decrease in its regulatory function. Furthermore, dehydration and heat buildup due to the heat make one more susceptible to heatstroke. Looking at tempera...