What climate does wine need?
Viticulture is only possible in certain areas of the earth, the so-called vine belts. These extend roughly between the 40th and 50th degrees of latitude in the northern hemisphere and between the 30th and 40th degrees of latitude in the southern hemisphere. Central and southern Europe, the USA, Chile, Argentina, South Africa, South Australia and New Zealand, for example, are located in these zones, where a temperate climate prevails.
The climate characteristics result from the sequence and interaction of various natural factors such as temperature, solar radiation, precipitation, humidity and wind. Whether a region is climatically suitable for the cultivation of grapevines is determined by its viticultural suitability, which is scientifically investigated and determined.
In order to form high-quality and ripe grapes, the vine needs above all warmth and light. Both are provided by the sun, so a south-facing slope is optimal for a vineyard. On slopes, moreover, the thermals are favourable: at night, cold air currents fall down the slope, and during the day, warm air currents rise up. This cycle is particularly important for white wines, as it is the only way for the grapes to form enough acidity. Water bodies (rivers, lakes, seas) also have a positive effect because they reflect the sunlight.
The minimum climatic requirements for viticulture are an average annual temperature of at least 9 degrees Celsius, an average temperature of the warmest month of at least 18 degrees Celsius, a maximum low temperature in winter of minus 13 degrees Celsius, at least 1,300 hours of sunshine per year, an annual rainfall of at least 500 mm (in warm climates at least 750 mm) and a vegetation period (the time between the last frost and the first frost) of at least 180 days. The optimal temperature for grape growth is between 25 and 28 degrees Celsius. The temperature depends largely on the altitude at which the vines are located; as a rule of thumb, the temperature drops by 0.6 degrees for every 100 metres of altitude difference upwards.
It is to be expected that climate change will shift or expand the wine-growing zones towards the poles in the coming years and decades. Against this background, the cultivation of vines at altitudes of 750 metres and above (so-called cool climate winegrowing) will also become increasingly important.
Besides the climatic conditions, the soil composition is the most important quality factor in viticulture