Global climate change models show that all regions of the U.S will experience increases in the frequency of extreme weather including both extreme droughts, and extreme wet periods. The ability to monitor the water stress status of wine grapes quickly, easily and inexpensively is a valuable tool for continuous future adaptation to a changing climate as well as improving current wine grape quality and yield. This paper presents a review and Proof of Concept data. A practical irrigation management technology based on simple Crop Water Stress Index (CWSI) measurements by growers is demonstrated. CWSI measurements were conducted in commercial vineyards in 2014 at three locations (Napa, Paso Robles California, and Deming NM) on four wine grape varieties, Chardonnay, Cabernet Sauvignon, Zinfandel, and Pinot Noir. The lower baseline of canopy temperature minus air temperature vs. vapor pressure deficit was measured at each site and grape variety. The upper base line was determined from measurements reported in the literature. The lower base line equations were the same for Pinot Noir and Chardonnay from Napa. The lower baseline of Cabernet Sauvignon from Napa and Deming were the same. The lower base line regression equation of Zinfandel from Deming had a similar slope but different intercept than the Cabernet Sauvignon, and the baseline equation was different from the Pinot Noir, and Chardonnay lower base line regression equations.