For decades, California winemakers have long thought of the Winkler Index as gospel. Developed in the 1940s by two professors at the University of California at Davis (U.C. Davis), the Index uses regional climate conditions to determine the best places to grow a wide range of wine grapes. With increasing pressures from heat and drought bearing down on the state, however, the Index may currently be horribly out of date. On July 22, U.C. Davis announced it would update the Index for the first time in more than 75 years.