öökülmade

An öökülm, or frost, is a meteorological phenomenon that occurs when the ground surface and plant tissues cool to below freezing point (0°C or 32°F) due to radiative cooling. This typically happens on clear, calm nights when there is little cloud cover or wind to insulate the surface. While the air temperature a few feet above the ground might be above freezing, the direct loss of heat from the surface causes localized freezing.

Öökülmad are most common in spring and autumn, particularly in inland areas or valleys where cold air can settle. They pose a significant risk to agriculture as they can damage or kill young plants, buds, and blossoms, especially those that have not yet developed frost resistance. Different plant species have varying degrees of tolerance to frost, and the timing of the frost in relation to the plant's growth stage is crucial.

Various methods are employed to protect crops from öökülmad. These include overhead irrigation, which releases latent heat as water freezes, wind machines to mix warmer air from above with the colder air at ground level, and covering sensitive plants with frost cloths or other protective materials. Understanding the likelihood and patterns of öökülmad is essential for farmers and gardeners to make informed decisions about planting times and protective measures.