CLIMATE

Tasmania has a cool temperate maritime climate, with surrounding seas and oceans moderating temperature extremes. Weather systems typically move across the State from the west, helped along by prevailing winds from the Southern Ocean.

Mild spring and summer seasons combine with warm and generally dry autumns to allow wine grapes to ripen slowly on the vine. This encourages maximum varietal flavour development with levels of natural acidity that give Tasmanian wines their characteristic freshness and balance.

Spring frosts and/or high humidity on some sites provide the greatest viticultural challenges.

In general, there is widespread variation in site attributes, such as vineyard slope and aspect, soil type, and meso-climate. Simply inferring that the State's southern vineyards are the industry's coolest and receive the most rainfall seldom rings true. Indeed, many of those located in the Coal River Valley outside Hobart figure among Tasmania's warmest and driest sites.

Heat summation data in Tasmanian vineyards ranges from below 1000 to 1300+ degree days.

The State's highest monthly rainfall totals are typically recorded during winter and spring. Modest totals during the growing season often prompt growers to provide supplementary drip irrigation on vineyard sites to relieve vine stress and promote healthy vegetative growth.

The Australian Government's Bureau of Meteorology allows access to climate and weather data.

Australia's climate is changing. According to the authors of Australia's Wine Future, average temperatures across all Australian wine regions are expected to increase by almost 3.0ºC by 2100. 

Tasmania's increase will be slightly less, but will exceed 2.0ºC. The island's wine industry will benefit somewhat from the moderating influences of the nearby Tasman Sea and Southern Ocean.

By 2041, Tasmania's smallest winegrowing district – the North West Coast – is predicted to be almost a full degree warmer during the growing season than the average now being experienced by the East Coast. North West Coast rainfall will decline from its annual average of 500mm to 442mm, barely 44mm more than the current figure for the East Coast.

The average growing season temperature on the East Coast will rise to 16.9ºC by 2100. That will bring this part of Tasmania roughly into line with present-day conditions in Robe (17.0ºC) on South Australia's Limestone Coast.

Many Tasmanian wine producers – including Freycinet, Gala Estate, Milton and Spring Vale on the East Coast – have planted Shiraz as a key measure of climate change adaptation.

Aridity – a measure of soil dryness that takes into account rainfall and evaporation – is also projected to increase in most Australian wine regions by 2100.

Declining winter rainfall will put water storages under stress across the country. Water conservation - as well as finding new water - will become increasingly critical issues for viticulturists.