Meteorological authorities in Japan released the first heatstroke warning notification of 2026, aimed at the capital Tokyo, the vast Kanto region and, specifically, the Ogasawara Islands, effective on the 23rd.
This is the inaugural notice of this type for the year 2026, covering metropolitan and adjacent areas. Particularly in the Ogasawara Islands, the forecast points to intense heat this Tuesday, June 23, considerably increasing the threat of heat stroke. The island nation, with its elderly population and increasingly harsh summers, makes preventing heatstroke a public health priority. It is crucial that the population adopts preventive measures.
Essential guidelines to avoid extreme heat
- Stay in air-conditioned environments: Use air conditioning consciously and stay in places with a pleasant temperature.
- Reduce sun exposure: Limit time outdoors, especially during hot periods, and use accessories such as umbrellas and hats.
- Stay hydrated constantly: Drink plenty of fluids and consume electrolytes, both indoors and outdoors.
- Pay attention to risk groups: Elderly people, children, people with chronic illnesses, disabilities or obesity require special care. Family members and caregivers must monitor the condition of these people.
- Administrators of public spaces and events: Check the heat index and advise attendees and participants on preventive measures.
For the 23rd, the forecast of the maximum values of the Heat Index (WBGT) in different locations includes: Ogouchi with 22, Ome with 23, Nerima with 24, Hachioji with 23, Fuchu with 24, Tokyo with 24, Edogawa Rinkai with 24, Oshima with 24, Miyakejima with 23, Hachijojima with 24 and Chichijima, which records the highest level, with 33.
Known by the acronym WBGT, or Wet Globe Temperature, the heat index serves as a crucial indicator of the danger of heat stroke, being determined by factors such as ambient temperature, relative humidity and the intensity of solar radiation. Japan’s Ministry of the Environment makes WBGT measurements available nationwide through its “Heatstroke Prevention Information Website.” It is recommended to consult this resource to check the risk levels in your location and adopt the appropriate preventive measures.
Classification of risk levels according to the WBGT index
- Above 31: Dangerous condition.
- Between 28 and less than 31: Requires extreme caution.
- From 25 to less than 28: Needs attention.
- Below 25: Indicates alert status.
Expected maximum temperatures for June 23 include: Tokyo at 28°C, Oshima at 26°C, Hachijojima at 25°C and Chichijima reaching 31°C.
The alert system is activated when the projected Heat Index (WBGT) reaches or exceeds 33, aiming to reinforce the importance of protection against excessive heat. Such announcements are usually released around 5 pm on the day preceding the forecast or at 5 am on the day itself. Additionally, in regions where an initial alert was issued late the previous afternoon, a subsequent update will be sent even if the latest morning analysis reveals changes.