Annual international event on May 3
Sun Day was designated by United States President Jimmy Carter, specifically devoted to advocacy for solar power, following a joint resolution by Congress, H.J.Res. 715 becoming Pub. L. 95–253. It was modeled on the highly successful Earth Day of April 22, 1970. It was the idea of Denis Hayes, who also coordinated Earth Day in 1970. The date became an international event in 1994.