気候変動対応型 打ち水大作戦 スタート!365日、暑い日は晴れたら毎日打ち水しよう

未来の打ち水アイデア募集!
打ち水大作戦

The old custom of sprinkling water with a ladle or by hand on the ground, called “uchimizu”, is a well-known example of the use of water in Japan’s daily living. People used to sprinkle water in their house entrances and gardens or in front of their shops to lay the dust and ease the heat3, which sometimes implies welcoming of guests.

Mission Uchimizu was launched as a great social experiment in 2003 in order to prove the hypothesis that we can lower the summer temperature by two degrees Celsius if one million people simultaneously do uchimizu (sprinkle water) on streets and gardens4.

  1. Taisho, regarded as the hottest day of the year on the lunar calendar
  2. Shosho, regarded as the day the summer heat begins to ease
  3. Water has a high heat of vaporization. As sprinkled water evaporates, it takes heat away from the ground.
  4. Mission Uchimizu has become a social action that millions of people in Japan take part in and doing uchimizu through the summer every year.

How to join

Warning: Preventing
Heat-related Illness.

Schedule uchimizu carefully and pace yourself.
Get enough water and replace salt & minerals to stay hydrated!
Please visit the following websites for more information on how to prevent heat-related illness.

Heat Stroke Alerts in Japan,
Ministry of the Environment of Japan

Tips for Preventing Heat-Related Illness,
Centers for Disease Control and Prevention (CDC), U.S. Department of Health & Human Services

Express your intention
to join & share your experience
after uchimizu

on social media using the hashtag #uchimizu and #打ち水大作戦.

Join us on Tuesday, August 1st to practice uchimizu over and over again.

The day-long mission

We call on you to practice uchimizu at home or in other places where you are, as often as possible from morning till night on August 1st rather than just once a day!
*Postponed in case of stormy weather.
How to do uchimizu

When the water you sprinkle has dried up, sprinkle more.

The air temperature will be lowered by the evaporation of sprinkled water. When the sprinkled water has dried up, the temperature no longer goes down. When the water you’ve sprinkled dries up, sprinkle (uchimizu) more! Roll up your sleeves and do uchimizu time and time again.

Lowering the temperature on August 1st

Can we make the air temperature on the day lower than the forecast of the previous day? Let’s cool off on a hot summer day by sprinkling water!
Express your intention to join & share your experience after uchimizu on social media using the hashtag #uchimizu and #打ち水大作戦.

Express your intention
to join & share your experience
after uchimizu

on social media using the hashtag #uchimizu and #打ち水大作戦.

Hoping water reached people in need. The water you sprinkle (uchimizu) will turn into blessed rain somewhere in the world.

#uchimizu

After sprinkling water,
share your experience on social media
with the hashtag #uchimizu and #打ち水大作戦