What is frost and what factors lead to its formation?

<p style=";text-align:left;direction:ltr">Arab Weather - Frost, one of the hydrometeorological phenomena.</p><p style=";text-align:left;direction:ltr"></p><h2 style=";text-align:left;direction:ltr"> <strong>What is frost?</strong></h2><p style=";text-align:left;direction:ltr"> <strong>Frost</strong> is considered one of the hydro-meteors, which indicates a drop in temperature to or below freezing.</p><p style=";text-align:left;direction:ltr"></p><h2 style=";text-align:left;direction:ltr"> <strong>How is frost formed?</strong></h2><ul style=";text-align:left;direction:ltr"><li style=";text-align:left;direction:ltr"> Frost occurs when the surface of the earth or the air in contact with the surface of the earth cools to zero or less than zero degrees Celsius.</li><li style=";text-align:left;direction:ltr"> Then the water turns into ice needle crystals and freezes as a result of the drop in temperature below zero degrees Celsius.</li></ul><p style=";text-align:left;direction:ltr"> Or when water vapor turns <strong>directly</strong> into small snow needles, and in order for this type of frost to occur, the surface on which ice crystals are deposited must be cooler than the ocean temperature.</p><p style=";text-align:left;direction:ltr"></p><h2 style=";text-align:left;direction:ltr"> <strong>Why does frost occur on the roof?</strong></h2><p style=";text-align:left;direction:ltr"> Because cold air is denser than hot air, in an atmosphere dominated by static winds, cold air gathers on the surface and here the temperature inversion occurs, and this explains the occurrence of frost on the surface.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>Frost is</strong> a water-meteorological phenomenon that threatens <a href="https://www.arabiaweather.com/content/%D8%AA%D8%B9%D8%B1%D9%81-%D8%B9%D9... production</a> , and <a href="https://www.arabiaweather.com/content/%D9%87%D8%B0%D9%87-%D9%87%D9%8A-%D... is no specific date for the occurrence of frost,</a> and the severity of frost varies from year to year.</p><p style=";text-align:left;direction:ltr"></p><h2 style=";text-align:left;direction:ltr"> <strong>How does the World Meteorological Organization (WMO) know frost?</strong></h2><p style=";text-align:left;direction:ltr"> Frost is defined as the low temperature near the surface of the earth and at a height between 5 cm and a height of 2 meters to below zero degrees Celsius, whether or not ice crystals are formed and adversely affect crops and lead to their damage.</p><p style=";text-align:left;direction:ltr"></p><h2 style=";text-align:left;direction:ltr"> <strong>Factors that lead to the formation of frost:</strong></h2><ul style=";text-align:left;direction:ltr"><li style=";text-align:left;direction:ltr"> Cold air mass flow.</li><li style=";text-align:left;direction:ltr"> Low humidity in the air, where the saturation degree is below zero percent.</li><li style=";text-align:left;direction:ltr"> Rapid cooling during the night we produce it to clear the sky from clouds.</li><li style=";text-align:left;direction:ltr"> Still air, as the layer in contact with the Earth&#39;s surface remains steadily cooling.<br /></li></ul><p style=";text-align:left;direction:ltr"> <strong>Also read:</strong></p><p style=";text-align:left;direction:ltr"> <a href="https://www.arabiaweather.com/content/%D9%83%D9%8A%D9%81-%D8%AA%D8%AD%D9... to protect plants from the threat of frost?</a></p><p style=";text-align:left;direction:ltr"> <a href="https://www.arabiaweather.com/content/%D9%85%D8%A7-%D9%87%D9%88-%D8%A7%D... is radioactive frost and what factors contribute to its formation?</a></p>