Worldwide Mission Uchimizu 2020. Can we lower the air temperature on the day? Let’s do uchimizu (sprinkle water) on Saturday, August 1st, 2020, from morning until night.

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 heat 2, 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 gardens3.

It will be an unusually hot summer this year.
And the new normal after covid-19 requires us to avoid going out.
Covering the mouth with a mask is needed, yet we are warned to beware of heat strokes.
Shops are requested to operate with their windows open for ventilation, so we want to bring a cool, natural breeze without depending only on air-conditioners.

It’s high time to do uchimizu.
When sprinkling and enjoying water,
Think about water,
Be thoughtful of the earth and people.

The new normal makes it hard for us to come together, to meet with friends and relatives far away.
Now let’s connect together by doing uchimizu simultaneously!

Worldwide Mission Uchimizu 2020:
Sprinkling water at home on August 1st, 2020,
from morning until night.

1 Participants are given discretion on whether to postpone if it rains.

2 Water has a high heat of vaporization. As sprinkled water evaporates, it takes heat away from the ground.

3 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

  1. Express your intention to join through this website.

  2. Let’s sprinkle water at home or in other places where you are, anytime from morning till night on August 1st!
    Click here to learn how to do uchimizu.

    how to do uchimizu
  3. After sprinkling water, please share your experience on social media using the hashtag #uchimizu.

  • The
    Day-long
    Mission

    It will be a particularly hot summer this year.
    We call on you to sprinkle water as often as possible throughout the day rather than just once a day!

  • 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 more! Roll up your sleeves and sprinkle water 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!

8月1日Express Your Intention
to join the Worldwide Mission
Uchimizu 2020

Thank you
for joining us!

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No. of people who will join0

Japan

*Uchimizu Month: from July 22nd4 to August 23rd5
Let’s sprinkle water on sunny days throughout the summer, not only on Worldwide Mission Uchimizu Day!

4 Taisho, regarded as the hottest day of the year in the traditional Japanese calendar

5 Shosho, regarded as the day the summer heat begins to ease

After sprinkling water,
share your experience on social media
with the hashtag #uchimizu.

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