Climatic condition, particularly in the natural environment, which primarily affects living organisms, water and soil, at a temperature below 0 °Celsius (32 °Fahrenheit). The air temperature is measured at a height of 1.25 metres above the ground, where temperatures are always slightly higher than on the ground. In meteorology, frost at ground level is referred to as ground frost. A distinction is made between radiation frost and adjective frost .

Radiation frost & adjective frost

Radiation frost occurs on dry, clear nights with no wind, when the heat radiated from the ground or plant tissue escapes unhindered into the atmosphere due to the absence of clouds, fog or haze. The coldest (and heaviest) air sinks to the ground and collects on the surface, preferably in low-lying depressions. The adjective (meaning "added") frost is caused by the inflow of already cooled air from other places. This can come from very distant areas such as a long valley.

Protection from frost

Protection can be achieved by taking appropriate measures when planting the vineyards. A hillside location from which the cold air flows into lower areas (air drainage) and high forms of cultivation are advantageous. Low-lying and flat areas are most at risk. Vineyards are controlled by wind machines (also by helicopter), which artificially mix the air with the warmer air in the upper layers. Warming smoke ovens or large heaters are also used. Artificial irrigation can directly warm the vines and the soil because heat is released when the water freezes or a thin layer of ice on plant parts also forms a protective coating.

The picture on the left shows the spraying with water and subsequent freezing of the vine buds as a protective measure against late frosts. The picture on the right shows a single frosted vine bud.

Late frost & early frost

In the northern hemisphere, frost in spring is generally referred to as late frost (also...