In addition to the above effects on quality wine production, climate generally constrains a given variety’s optimum ripening conditions to a narrow geographic zone, putting the grapevines at a greater potential risk from climatic variations and change than crops with a broader geographic range. Furthermore, wine has devel- oped as a key economic sector with broad historical, social, and cultural identity derived from grape growing and production (e.g., Bordeaux, France). Based on the cultural and economic importance of viticulture, extensive evidence of historical responsiveness to climate change, and the potential impacts that may come from future climate change, this research studies the nature and trends of climate and wine quality for 27 of the most prominent wine growing regions in the world. The analysis differs from earlier studies in that it includes multiple regions and covers a greater length of time. The research examines: 1) the observed changes seen in growing season temperatures; 2) the variation and trends in vintage ratings; 3) the relationship between observed climate and vintage ratings; and 4) the projected growing season temperature changes from a climate model.