Term for a climatic period of long drought due to no or very little precipitation (rain). A special form is winter drought, which is caused by prolonged frost. The complex interrelationships of soil water supply, air temperature and humidity are important for assessing the negative impact on viticulture. This also depends on the area and the climate prevailing there. In normally cool and humid wine-growing regions, drought or dryness can also be advantageous, especially for the production of red wine, if the reduced growth results in a natural, quality-enhancing yield restriction.
In extreme cases, however, this leads to water stress (drought stress), which has a negative effect on yield and wine quality, especially at the time of maturation (ripening). In Europe, this is usually the months of August to September. In combination with high daytime temperatures above 40 °C, heat stress also occurs. In hot and dry regions with too little rainfall, artificial irrigation is used as a preventive measure. This is common practice in southern countries or overseas such as Australia or South America. Within the EU, such measures are usually the exception or subject to approval.