Like many agricultural products, wines are deeply affected by climate conditions. In viticulture, climate is the word that indicates the weather conditions of a certain area during the growth cycle of the grape: from bud break in spring to leaf fall in autumn. In winter, grapevines are dormant during a phase called, indeed, dormancy.
Depending on the extension of the area affected by a specific climate, we refer to “macro-climate” when pointing out a wine region, to “meso-climate” when the extension of a vineyard is indicated and to “microclimate” for a specific row of vines.
Suitable climates for viticulture are normally found between the 30th and 50th parallel of both the Northern and Southern Hemisphere. Outside those latitudes, conditions are believed to be either too hot or too cold to suit grape cultivation. At high altitudes and latitudes, particularly cold conditions are usually identified as “marginal climates”: vintages in these climates tend to vary from year to year in a remarkable and quite interesting way.
Atmospheric conditions can impact the growth cycle of the grapes in many different ways. Optimal temperature, light intensity, rainfall and wind positively affect certain varieties, whereas the contrary would not allow for optimal and risk-free growth. For example, water is essential to plant survival: however, too much rain might cause diseases such as mold and mildew, while not enough rain will result in drought conditions.
Macro-climate must be factored in by growers, for example, when choosing the type of grapes to be planted. Some varieties would be automatically discarded in certain areas simply because conditions are not ideal.
Other factors, such as wind, rainfall, or light intensity, can be partially kept under control thanks to vineyard architecture and spatial techniques, that maximise or minimise – risk wise – the performance of grapevines.
In viticulture there are three distinctive macro-climates. In some areas, it’s not uncommon to find hybrid climatic zones characterised by more than one climate.
It’s by far the warmest climate to cultivate grapevines. It is characterised by very little seasonal changes and stable warm temperatures. As for the problems linked to Mediterranean climates, water scarcity and drought hazards often call for supplemental irrigation.
This macro-climate can be found in Tuscany and Sicily, in Italy, as well as Southern Rhône in France. New South Wales, Western and South Australia, as well as Napa are considered examples of regions that enjoy a Mediterranean climate outside Europe.
Continental climates are common in areas located far from large bodies of water, normally protected by relatively close mountains. Not only they are characterised by significant seasonal variations, with hot summers and cold winters, but they also present a notable difference in day and night temperatures during the growing season. This environmental factor is believed to impart complexity to the wines.
This climate is found in the Northern Hemisphere, with Burgundy, Piedmont, Northern Rhone, Loire and Rioja being the most famous areas. A rare example in the Southern Hemisphere is the Argentinian Mendoza.
Also considered the middle ground between a Mediterranean and Continental climate, a Maritime climate also known as oceanic climate, is likely to be found in regions in proximity to large bodies of water, such as the oceans. The growing season lasts for quite long, however temperatures are milder than under Mediterranean conditions. Rainfalls can be quite intense.