What Is Earth Hour? When Is Earth Hour 2026 and Why Do People Turn Off Lights?
Earth Hour is a global WWF movement that encourages people to switch off non-essential lights for one hour and spend that hour doing something positive for the planet. It takes place every year on the last Saturday of March from 8:30 PM to 9:30 PM local time. In 2026, Earth Hour falls on March 28. It’s a perfect moment to spend time outdoors, look up, and explore the night sky with Sky Tonight. Read on to learn more about Earth Hour.
Contents
- What is Earth Hour?
- When is Earth Hour?
- How do we celebrate Earth Hour?
- Earth Hour criticism
- What do astronomers mean by light pollution?
- F.A.Q
- Earth Hour Explained: Bottom line
What is Earth Hour?
Earth Hour is an annual global movement organized by the World Wide Fund for Nature (WWF) that encourages people to switch off non-essential lights for one hour and take action for the planet. Its purpose is to promote more sustainable habits and draw attention to climate change, biodiversity loss, and light pollution.
The iconic tradition of Earth Hour is to turn off the lights for 60 minutes. Of course, it’s not the only thing: the main idea is to make people reevaluate their consumption habits and become more eco-friendly in their daily lives. But it's a rather simple symbolic action anyone can do – no special knowledge, equipment, or excessive effort needed.
The first Earth Hour was held in Sydney in 2007, and the movement later spread worldwide. In recent years, supporters across more than 180 countries and territories have taken part in Earth Hour and related “Give an hour for Earth” activities.
Major landmarks, such as the Sydney Opera House, the Colosseum, and the Eiffel Tower, go dark on Earth Hour. This action is remarkable and trends on social media, drawing more and more attention to the Earth Hour movement and the ideas it promotes.
Note: Earth Hour is not the same as Earth Day. Earth Hour is held in late March, while Earth Day is celebrated on April 22.
When is Earth Hour?
Earth Hour is held every year on the last Saturday of March, from 8:30 PM to 9:30 PM local time. In 2026, Earth Hour falls on March 28.
There’s a reason why Earth Hour is held in late March. Around this time, the vernal equinox occurs, when day and night are nearly equal worldwide. It provides the greatest visual impact for a ‘lights out’ event worldwide.
How do we celebrate Earth Hour?
You can simply turn lights off for an hour, but why stop there? At home, you can play board games, do yoga while listening to an Earth Hour-themed meditation track or have a candle-lit dinner – bonus points for a waste-free meal.
Possible outdoor activities include picking up trash, running, cycling, camping, and, of course, stargazing – use our Sky Tonight app to learn what you can see at the moment in the night sky. Look up at the stars and think about the ways to protect our planet Earth, which is so small and fragile.
Whatever you do, don’t forget to spread the word about Earth Hour – tell your friends and family, make a post on social media, involve as many people as you can to raise awareness about the challenges our planet is facing. That is the main point of Earth Hour, after all.
Earth Hour criticism
Some critics argue that Earth Hour does more harm than good or has little measurable effect beyond symbolism. Earth Hour is criticized as an ineffective “feel-good'' event that makes people think they are saving nature, while in reality, the event produces little to no effect on carbon emissions and other problems. Moreover, some environmentalists believe Earth Hour blames climate change on individuals and releases fossil fuel companies and politicians from their responsibility.
But the thing is the governments and businesses do get involved and use Earth Hour as an occasion to initiate environmental laws and programs. For example, Argentina used its 2013 Earth Hour campaign to help pass a Senate bill for a 3.4 million hectares Marine Protected Area in the country.
For individuals, Earth Hour might be a good chance to rethink their way of life. Many people participate in Earth Hour-themed events and learn what they could do for the planet every day. It’s important to understand that one hour without electric light is just a start for further actions throughout a year.
Astronomy lovers should especially support the Earth Hour movement. The less light pollution we produce, the more stars we get to see!
What do astronomers mean by light pollution?
Light pollution is the presence of excessive, misdirected, or obtrusive artificial light, usually outdoors. Excessive light pollution has consequences: it disrupts ecosystems, has adverse health effects, and wastes energy. In terms of astronomical observations, city lights brighten the night sky and reduce the contrast of celestial objects, making them more difficult to see. That’s why astronomers nowadays have to use light pollution filters and conduct their observations away from big cities.
Light pollution also affects the day-night cycle that nature, animals, and humans depend on. The good news is light pollution can be easily reversed, unlike any other. We just have to reduce using non-essential lights – and Earth Hour is a good opportunity to try.
Want to know how light-polluted your sky is? Check out our infographic, which uses a simple system to show how dark or bright your sky is. It ranges from Class 9 (lots of city lights and little to no visibility of the sky) to Class 1 (really dark and great for stargazing).
F.A.Q
When and where did the concept of Earth Hour begin?
In 2004, WWF Australia had started looking for ideas for engaging Australians into climate change issues. The idea was coined in 2006 and brought to life in 2007: the first Earth Hour was held in Sydney on March 31, 2007.
What countries participate in Earth Hour?
Starting with 35 countries and 400 cities in 2008, by now Earth Hour has united more than 190 countries including China, Bulgaria, India, Japan, Russia, Turkey, Uganda, and others.
Why do people turn off lights for Earth Hour?
Turning off lights is the main symbol of your commitment to the Earth Hour movement. This is a simple action that helps to draw attention towards serious environmental issues.
Is Earth Hour a charity?
Earth Hour is the initiative of the WWF, which is an international non-governmental organization.
Is Earth Day the same as Earth Hour?
No, although they have similar purposes. Earth Day is an annual event held on April 22 for people worldwide to stage events and discuss environmental issues. This date was chosen with the expectation that it does not fall on exams or spring break, so that as many students as possible can participate.
Learn more: Earth Day: When Is the Earth’s “Birthday”?
Can you use your phone or watch TV during Earth Hour?
The point of Earth Hour is to turn off non-essential electrical devices. It's not about giving up electricity altogether. Just try to make your phone or TV the only device you use during Earth Hour.
Earth Hour Explained: Bottom line
Earth Hour is a global movement held every year on the last Saturday of March from 8:30 PM to 9:30 PM local time. It encourages people to switch off non-essential lights for one hour, think more consciously about energy use, and take simple steps that benefit the planet. For astronomers and skywatchers, Earth Hour is also a reminder that reducing unnecessary lighting helps protect dark skies and makes stargazing more enjoyable.
