Occurring in late summer / autumn frost; look there.
Climatic condition at a temperature below 0 ° Celsius. In general, the air temperature is measured at a height of 1.25 meters above the ground; At this altitude, the temperatures are always slightly higher than on the ground. In meteorology, frost at the level of the ground is called ground frost . Basically, a distinction is made between radiation frost and adjective frost . Radiation frost occurs on dry, clear nights with no wind, when lack of clouds, mist or haze escaping from the ground or the plant tissue heat escapes unhindered into the atmosphere. The coldest (and heaviest) air sinks to the bottom and collects on the surface, preferably in low-lying hollows. The adjective (aka "attached") frost is caused by the inflow of already cooled air from other places. This can be done from very distant areas such as through a long valley.
Even when creating the vineyards can be achieved by appropriate measures a certain protection. A hillside, from which the cold air flows into deeper areas (air drainage), as well as high education forms are of great advantage. Low-lying and flat areas are the most vulnerable. A frost control in the vineyard is done by so-called wind machines (or even by helicopters), with which a mixture with the warmer in the upper layers of air artificially induced (see also wind ). Also warming smoke ovens, large heaters and similar means are used. Artificial irrigation can be used to directly heat the vines and the soil, because when the water freezes, heat is released or a thin layer of ice on plant parts additionally forms a protective sheath.
In the northern hemisphere, frost is generally referred to as late frost in the spring...