climatic regions

Definition

Wine

  • in California, US, regions are categorised according to a system of measuring the amount of heat received from the sun during a growing season. The measurement is then used to help identify the suitability of the region for a particular type of grape and wine production. The units of heat from the sun are measured in ‘degree days’ on the Fahrenheit scale that allow the region to be classed into one of five regions: Region I has up to 2,500 degree days of heat per year, Region II has between 2,501 and 3,000 degree days of heat per year, Region III has between 3,001 and 3,500 degree days of heat per year, Region IV has between 3,501 and 4,000 degree days of heat per year and Region V has above 4,000 degree days of heat per year. Most wine production is found in areas in Regions I, II and III, but the optimum region varies according to the variety of grape.
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