The Adelaide Hills Wine Region includes all areas of the Adelaide Hills that have an elevation greater than 300m. Elevation has two major impacts on grape growing; temperature and rainfall.
Elevation results in cooler temperatures as, for every 100 metres increase in height, the temperature drops by roughly 0.5°C. This is particularly important at night in the final stages of ripening when colour and flavour compounds are enhanced by cool conditions. Elevation also results in higher rainfall when clouds are lifted as they move across the hills.
Mean January Temperature (MJT) is a measure that is used in Viticulture to indicate how warm a region is during the growing season. The MJT for Adelaide, for example, is 23.3°C whilst Stirling (in the Adelaide Hills just out of Adelaide) is 18.2°C even though it is only 15kms from Adelaide. Stirling is one of the cooler areas in the region. For comparison Kersbrook, in a warmer area, has an MJT of 20.2°C.
In terms of annual rainfall for these three sites, Adelaide averages 550mm per year, Kersbrook has 690mm and Stirling 1200mm. The elevations for these three sites are respectively 62m, 353m and 496m for Stirling.