International Dark Sky Week 2025 invites the world to discover and protect the night - DarkSky International

International Dark Sky Week (IDSW) returns as the world’s largest celebration of dark skies (April 21–28, 2025) inviting people everywhere to discover the wonders of the night, understand the importance of natural darkness, and take meaningful action to protect a resource increasingly at risk of being lost.

First launched in 2003 by a high school student with a passion for astronomy and stargazing, International Dark Sky Week has since grown into a global movement—building awareness and appreciation for dark nights and their vital role in supporting human health, sustaining critical wildlife habitat, advancing scientific discovery, and preserving a shared cultural heritage.

International Dark Sky Week also brings attention to the growing threat of light pollution—the excessive and misdirected use of light at night—continuing to increase at an alarming rate of 9.6% globally each year. The week serves as both a powerful campaign to highlight the damaging impacts of this unchecked environmental threat, as well as a catalyst for change, inspiring action worldwide.

Each year, DarkSky International takes a leading role in organizing and promoting this global event alongside its worldwide network of Advocates, official chapters, certified International Dark Sky Places, and community partners. Together, they provide accessible and engaging ways for anyone, anywhere to participate—from contributing to the Globe at Night citizen science campaign that tracks light pollution trends, to encouraging local proclamations that recognize the importance of dark skies.