Earth Hour 2025: London To Be Plunged Into Darkness Again

By Laura Reynolds

Last Updated 10 February 2025

Laura Reynolds Earth Hour 2025: London To Be Plunged Into Darkness Again

Earth Hour in London: People gathered in Trafalgar Square by candlelight, with the silhouette of Nelson's Column visible in the sky, and a few street lights on the opposite side of the square — A previous Earth Hour in Trafalgar Square. Photo: Magnus D via creative commons

WWF's Earth Hour returns to London (and indeed the whole planet) this March, plunging us temporarily into darkness.

You probably know the Earth Hour drill by now — it's been running since 2007 after all. Switch your lights off for an hour on a Saturday evening to show your dedication to caring for the planet.

Earth Hour 2025: a five-storey building with all the lights switched off — The Foreign and Commonwealth Office taking part in Earth Hour. Image: Foreign and Commonwealth Office

Landmarks including the BT Tower, Harrods, the Royal Naval College, Tower Bridge, Southwark Cathedral, Mansion House, Barbican, the Gherkin, St Paul's and the Royal Opera House have taken part in previous years, making for an unusual view of the London skyline.

Only non-essential lights are switched off, and street lights remain on for safety reasons — though in a city like London, that means rather a lot of bulbs remain on, so in practise it rarely reaches anything close to pitch black. Check back on the Earth Hour website or with individual venues to find out what's going dark this year.

Earth Hour London: The O2 in the dark, with only the safety lights on the masts illuminated — Safety lights remain on, such as those highlighting obstacles for planes landing at City Airport. Phew. Photo: Matt Buck via creative commons

The WWF is encouraging people to go one step further for Earth Hour, and give 60 minutes of their time to doing something positive for the planet. Planting a tree, going litter picking or cooking a sustainable meal are among the suggestions. Check out the Give an Hour for Earth section of the website.

Earth Hour 2025 takes place Saturday 22 March 2025 at 8.30pm.