600kg of Tomatoes Destroyed by Extreme Heat: The Double Whammy of "Heatwave × Record-Breaking Short-Term Heavy Rain" Strikes Western Japan

600kg of Tomatoes Destroyed by Extreme Heat: The Double Whammy of "Heatwave × Record-Breaking Short-Term Heavy Rain" Strikes Western Japan

2025年07月03日 19:40

1. The Beginning: Heatwave and Heavy Rain Hit on the Same Day

Western Japan was covered by high pressure from the early hours of July 2, recording 37.6°C in Kurume and Ebino. In the afternoon, atmospheric instability led to approximately 100 mm of rain per hour in Ukyo Ward, Kyoto City, prompting the announcement of "Record-Breaking Short-Term Heavy Rain Information."tenki.jpweathernews.jp



2. The Tragedy in the Greenhouse: 600 kg of Tomatoes Wither

At Kazahaya Yamamoto Farm in Matsuyama, Ehime, the temperature inside the greenhouse reached nearly 40°C daily, causing 3,000 plants to wilt rapidly. All 600 kg, which were scheduled for harvest, had to be discarded. Katsuki Yamamoto, a farmer with 24 years of experience, lamented, "It's like dried tomatoes; all my efforts have come to nothing."news.tv-asahi.co.jpfnn.jp



3. Why Are Tomatoes Vulnerable to Heat?

  • Optimal Temperature: 24–28°C during the day, 15–18°C at night

  • Photosynthesis enzymes deactivate above 35°C, causing fruit to become "boiled"

  • Cell walls are destroyed due to a combination of heat and water stress



4. The Fastest Heatwave Day and Hottest June on Record

According to the Japan Meteorological Agency, the average temperature in June 2025 was +2.34°C, the highest on record. Matsuyama recorded over 35°C on June 16, the earliest in observation history.tenki.jpnews.tv-asahi.co.jp



5. The Mechanism Behind Simultaneous Extreme Phenomena

  • Stagnation of clear weather areas due to Pacific High Pressure Blocking

  • Moist westerly short waves enter the edges, developing cumulonimbus clouds in a linear pattern

  • Urban heat islands amplify rainfall intensity (latest radar analysis)



6. Risks to Agriculture and Food

  1. Shift in Production Areas: Transition to heat-resistant Okinawa and Kyushu production → Increased logistics costs

  2. Varietal Change: Introduction of heat-tolerant tomatoes (e.g., improved Sunroad varieties)

  3. Smart Agriculture: AI-controlled ventilation, mist cooling, and CO2 fertilization to compensate for photosynthesis efficiency



7. Impact on Cities and Caution for Foreign Tourists

  • Heatstroke transports increased by 35% year-on-year in Kyushu and Chugoku regions

  • Tourist areas (Kyoto and Nara) were flooded by short-term heavy rain, disrupting transportation networks

  • The disaster English broadcast app "Safety tips" is essential



8. Government and Local Government Responses

  • Heatstroke Warning Alert: Simultaneously issued in 17 prefecturesweathernews.jptenki.jp

  • Ministry of Agriculture, Forestry and Fisheries: Plans to establish emergency heavy rain and high-temperature countermeasure subsidies

  • Japan Meteorological Agency: To accelerate the linear precipitation band prediction model to update every 10 minutes



9. International Comparison and Implications

Japan's tomato self-sufficiency rate is about 77%. If imports for processing increase, it could affect global market prices. Abnormal high temperatures are occurring simultaneously in northern Italy and California, indicating that Mediterranean-type damage is becoming a norm in Asia as well.



10. Conclusion

In 2025, Japan has entered a new phase where conflicting extreme phenomena, such as "excessively hot early summer" and "guerrilla heavy rain," occur simultaneously. This poses risks that could affect travel plans, business supply chains, and food culture experiences for foreigners, making real-time weather and agricultural information checks essential.


List of Reference Articles

  • TV Asahi News "600kg of Tomatoes 'Destroyed'... Heatwave Days Continue in Western Japan, 'Record-Breaking Short-Term Heavy Rain Information' Also Frequent" (2025/07/03)news.tv-asahi.co.jp

  • FNN Prime Online "Never Seen Anything Like This in 24 Years: Severe Impact on Tomatoes Due to Heatwave" (2025/06/30)fnn.jp

  • Japan Meteorological Association tenki.jp "First Heatwave Day of the Year in Osaka, Extreme Heat Nationwide" (2025/07/01)tenki.jp

  • Weather News "About 100mm of Torrential Rain in Kyoto Prefecture in One Hour, Record-Breaking Short-Term Heavy Rain Information" (2025/07/02)weathernews.jp

  • Japan Meteorological Agency "Heatstroke Warning Alert Announced in 17 Regions" (2025/07/03)weathernews.jp

  • TV Asahi News "Hottest June in Japanese History, This Summer Expected to Be Hotter than 2024" (2025/07/02)news.tv-asahi.co.jp

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