'Heatstroke' is a Preventable Meteorological Disaster: Releasing the 'Towards Zero Heatstroke: Heat Acclimatization Front (1st Edition)' for 2026
The Japan Weather Association will publish the 2026 'Heat Acclimatization Front' on April 9 to prevent spring heatstroke. Following the record-breaking heat of 2025, the project encourages people to consciously sweat and acclimatize their bodies to heat before summer fully arrives.
📋 Article Processing Timeline
- 📰 Published: April 9, 2026 at 23:00
- 🔍 Collected: April 13, 2026 at 20:31 (93h 31m after Published)
- 🤖 AI Analyzed: April 19, 2026 at 19:19 (142h 47m after Collected)
The "Towards Zero Heatstroke" project (hereafter, this project), promoted by the general incorporated foundation Japan Weather Association (Headquarters: Toshima-ku, Tokyo, Chairman: Kazuhiro Watanabe, hereafter "Japan Weather Association"), will release the "Towards Zero Heatstroke: Heat Acclimatization Front (1st Edition)" on its official website (https://www.netsuzero.jp/le15-zensen) on Thursday, April 9, 2026. This aims to widely disseminate the importance of "Heat Acclimatization (*1)," which means getting the body used to the heat beforehand, prior to the arrival of full-scale heat. It provides a guideline for the timing when heat acclimatization becomes necessary in each region. This project has been continuing to convey the importance of heat acclimatization by publishing content on it on its official website since 2021.
*1 What is Heat Acclimatization?
One of the heatstroke countermeasures that can be taken before it gets hot is building a body that is resistant to heat. To build a body strong against heat, in addition to a well-balanced diet and sufficient sleep, it is also important to practice "heat acclimatization." Heat acclimatization means the body gets used to the heat. If you are not heat-acclimatized, your body cannot effectively release heat to the outside, increasing the risk of heatstroke. Although there are individual differences, heat acclimatization takes a few days to about two weeks. Allow your body to get used to the heat with plenty of time before it actually gets hot.
About Heat Acclimatization (Details) https://www.netsuzero.jp/learning/le15
■ What is the "Towards Zero Heatstroke: Heat Acclimatization Front"?
The "Towards Zero Heatstroke: Heat Acclimatization Front" shows the guideline timing to begin heat acclimatization—getting the body used to the heat by consciously sweating through light exercise or bathing in a tub.
Last year's (2025) average temperature deviation from June to August significantly exceeded the records of 2023 and 2024 (+1.76°C) and recorded the highest value (+2.36°C). On August 5, 2025, a maximum temperature of 41.8°C was recorded in Isesaki City, Gunma Prefecture, breaking the all-time highest temperature record in Japan. Furthermore, the number of locations observing maximum temperatures of 40°C or higher reached a record high of 30, and the number of extreme heat days (maximum temperature of 35°C or higher) observed at AMeDAS stations nationwide from June to August totaled 9,385 locations, the highest since 2010, marking a series of record-breaking heat events.
Temperatures this April are expected to be higher than normal nationwide, and sudden heat is anticipated. Just as in sunny environments outdoors, please be careful of heatstroke indoors depending on the conditions.
■ Heat Acclimatization Started in April-May Prevents Spring Heatstroke
At the April-May timing when many people have not yet acclimatized to the heat, please be especially careful of "spring heatstroke." Be conscious of heat acclimatization early on and build a body that won't succumb to the heat. Consciously sweating within a reasonable range, such as through light exercise or bathing in a tub, leads to prevention. In addition, before the full-scale summer arrives, it is important to raise disaster prevention awareness against heatstroke and "prepare" by inspecting and test-running air conditioners and gathering heat countermeasure items. Think of heatstroke as a meteorological disaster where damage can be reduced by preparing in advance, just like typhoons or heavy rains, and protect yourself and those around you from the heat.
[Towards Zero Heatstroke: Preparing for the Heat] https://www.netsuzero.jp/learning/le20
In this project, along with the guideline timing to start heat acclimatization, specific methods for heat acclimatization will be regularly updated on the official website and the official X (formerly Twitter) account (@netsuzero2013).
Additionally, "Towards Zero Heatstroke" plans to announce the "Towards Zero Heatstroke: Heat Acclimatization Front (2nd Edition)" around early June, before the peak summer heat arrives.
■ Heat Acclimatization Point Manual
On the "Heat Acclimatization" content page of the "Towards Zero Heatstroke" project, a printable "Heat Acclimatization Point Manual" is also available. This manual deepens knowledge about heat acclimatization and clearly summarizes points that can be incorporated into daily life.
You can use the point manual from the link below.
"Heat Acclimatization Point Manual" Download Page
https://www.netsuzero.jp/images/learning/le15/download_pdf01_2026.pdf
■ Future Weather Trends
Japan Weather Association / Meteorologist / Disaster Prevention Specialist / Heatstroke Prevention Instructor
*1 What is Heat Acclimatization?
One of the heatstroke countermeasures that can be taken before it gets hot is building a body that is resistant to heat. To build a body strong against heat, in addition to a well-balanced diet and sufficient sleep, it is also important to practice "heat acclimatization." Heat acclimatization means the body gets used to the heat. If you are not heat-acclimatized, your body cannot effectively release heat to the outside, increasing the risk of heatstroke. Although there are individual differences, heat acclimatization takes a few days to about two weeks. Allow your body to get used to the heat with plenty of time before it actually gets hot.
About Heat Acclimatization (Details) https://www.netsuzero.jp/learning/le15
■ What is the "Towards Zero Heatstroke: Heat Acclimatization Front"?
The "Towards Zero Heatstroke: Heat Acclimatization Front" shows the guideline timing to begin heat acclimatization—getting the body used to the heat by consciously sweating through light exercise or bathing in a tub.
Last year's (2025) average temperature deviation from June to August significantly exceeded the records of 2023 and 2024 (+1.76°C) and recorded the highest value (+2.36°C). On August 5, 2025, a maximum temperature of 41.8°C was recorded in Isesaki City, Gunma Prefecture, breaking the all-time highest temperature record in Japan. Furthermore, the number of locations observing maximum temperatures of 40°C or higher reached a record high of 30, and the number of extreme heat days (maximum temperature of 35°C or higher) observed at AMeDAS stations nationwide from June to August totaled 9,385 locations, the highest since 2010, marking a series of record-breaking heat events.
Temperatures this April are expected to be higher than normal nationwide, and sudden heat is anticipated. Just as in sunny environments outdoors, please be careful of heatstroke indoors depending on the conditions.
■ Heat Acclimatization Started in April-May Prevents Spring Heatstroke
At the April-May timing when many people have not yet acclimatized to the heat, please be especially careful of "spring heatstroke." Be conscious of heat acclimatization early on and build a body that won't succumb to the heat. Consciously sweating within a reasonable range, such as through light exercise or bathing in a tub, leads to prevention. In addition, before the full-scale summer arrives, it is important to raise disaster prevention awareness against heatstroke and "prepare" by inspecting and test-running air conditioners and gathering heat countermeasure items. Think of heatstroke as a meteorological disaster where damage can be reduced by preparing in advance, just like typhoons or heavy rains, and protect yourself and those around you from the heat.
[Towards Zero Heatstroke: Preparing for the Heat] https://www.netsuzero.jp/learning/le20
In this project, along with the guideline timing to start heat acclimatization, specific methods for heat acclimatization will be regularly updated on the official website and the official X (formerly Twitter) account (@netsuzero2013).
Additionally, "Towards Zero Heatstroke" plans to announce the "Towards Zero Heatstroke: Heat Acclimatization Front (2nd Edition)" around early June, before the peak summer heat arrives.
■ Heat Acclimatization Point Manual
On the "Heat Acclimatization" content page of the "Towards Zero Heatstroke" project, a printable "Heat Acclimatization Point Manual" is also available. This manual deepens knowledge about heat acclimatization and clearly summarizes points that can be incorporated into daily life.
You can use the point manual from the link below.
"Heat Acclimatization Point Manual" Download Page
https://www.netsuzero.jp/images/learning/le15/download_pdf01_2026.pdf
■ Future Weather Trends
Japan Weather Association / Meteorologist / Disaster Prevention Specialist / Heatstroke Prevention Instructor