Definition - What does Sub-Tropic Region mean?
A sub-tropic region is a viticultural term used to describe the climate and growing conditions of regions between the 25th and 40th latitudes. All agricultural and wine regions are categorized by the overall average of their characteristics during the region's growing season. A sub-tropic region is defined as one that is defined as a geographic region that has a Koppen climate classification of above 22 °C (72 °F) in the hottest month and 0 °C (32 °F) or −3 °C (27 °F) in the coldest month.
WineFrog explains Sub-Tropic Region
Climate plays an integral role in agriculture and viticulture, as climate is one of the most influencing factors next to soil that determines how well a crop or a wine vine will do in a region. It is important to match the wine grape varietals with the best climate to ensure that the vine produces grapes that have exceptional flavor, acidity and a high brix level at harvest.
Sub tropic regions are defined by their average temperatures through the growing season and geographic locations. Sub tropic regions are known to have warm to hot summers, cooler winters, but rarely have frost. Sub-tropic regions can also be classified as having a humid/wet or dry climates. In regions with humid /wet sub-tropic regions can experience heavy rainfall while dry regions have little to no rain. Dry sub-tropic climates produce grapes with a softer acidity, higher brix and fully developed fruit flavors. Notable sub tropical wine regions include the southern United States, Australia and the high altitude wine regions in Argentina.