The Washington State Climate Office (WASCO) was first established in 2003, and temporarily supported by the WA State Department of Ecology in 2004. Originally called the Office of the Washington State Climatologist, the Office was renamed to WASCO in 2024. WASCO received American Association of State Climatologists (AASC)-recognized State Climate Office status as climate service capabilities and state and federal partnerships grew. In 2007, the legislature established state funding for the Office. In 2023, WASCO became an EarthLab member organization, housed within the University of Washington Climate Impacts Group. 

The Office fills a valuable niche in Washington State, with a focus on current and past climate, providing training and capacity building, data and information resources, and pursuing applied research on climate and its impacts.