The size of the region, by implication, results in variations in climate, geology and topography. The main variations are apparent as one travels north. 

The north is drier than the south and typically receives an average of 5-10mm less rain per month during the
vines growing season (October to April). The region's southern vineyards experience cooler temperatures during the growing season.  These can vary between 1.8 and 1.4 degrees Celsius lower, resulting in an extended growing season.  This variation in temperature during the grape ripening period results in a spread of picking dates and subsequently the development of a range of different flavour profiles.