If you haven't noticed, it's been pretty hot in Tokyo lately. Even with cooling products and other summer essentials on hand to help combat the blazing temperatures, heat-related health risks still remain. According to the Tokyo Fire Department, there were 7,996 incidents of heatstroke between June and September of last year, and given that this year is just as hot, it's important to know the risks before going out. To help people better prepare themselves against the heat, the Tokyo Metropolitan Government has launched the 'Tokyo heat map'.
The city map displays hourly measurements in seven colour-coded tiers ranging from 'generally safe' (below 21) to 'disaster-level danger' (35 and up). At the bottom of the screen you can toggle through times to view measurements up to 48 hours in advance, while selecting any of the black circles on the map will lead to a more detailed breakdown of that area's data. The numbers displayed don't represent the standard temperature as we know it, though.
Instead, the map shows what's called WGBT, or 'wet-bulb globe temperature', which factors in not only air temperature, but several other metrics like humidity, wind speed and cloud cover. The resulting number is a type of heat index that offers a more accurate indicator of heat-related stress on the body than a standard thermometer. You can find the map here (in Japanese only).
If you feel the WGBT getting too high for your liking while you're out, know this: The metro government has also published a list of 'cool shelters', which includes air-conditioned locations like ward offices and libraries, where you can take a breather. You can search the full list of the 2,500-plus venues here, but given that it's all in Japanese and a bit of a chore to navigate anyway, you honestly may as well just pop into a konbini if you need to cool down.
In addition to the heat map, we recommend keeping an eye on the Ministry of the Environment's nationwide heatstroke alert system (in English), which runs from now through October 22. Until then, remember to stay hydrated and avoid overexertion when out in the summer heat.
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