This report, required by state law under HB3543, provides a comprehensive assessment of the state of science of climate change as it pertains to Oregon, covering the physical, biological, and social dimensions. The first chapter summarizes the current state of knowledge of physical changes in climate and hydrology, focusing on the period since the previous Oregon Climate Assessment Report (OCAR3, Dalton et al. 2017); and the second chapter covers the impacts. The second chapter is, verbatim, the Northwest chapter of the Fourth National Climate Assessment (NCA4) which was released by the federal government November 23, 2018. It is available for download separately: https://nca2018.globalchange.gov/downloads/NCA4_Ch24_Northwest_Full.pdf