0 °C, 32 °F, 273.15 K. The temperature of air below the freezing point of water i.e (0 °C, 32 °F, 273.15 K). Usually measured at the height of 1.2 m from the ground surface.
Frost forms when the temperature of a solid surface in the open cools to below the freezing point of water and for the most clearly crystalline forms of frost in particular, below the frost point in still air. Frost is the coating or deposit of ice that may form in humid air in cold conditions, usually overnight. In temperate climates it most commonly appears as fragile white crystals or frozen dew drops near the ground, but in cold climates it occurs in a greater variety of forms. Dew Point Temperature and Frost Point Temperature. The temperature at which the change of state occurs as the air is cooled is called the dew point temperature when the change of state occurs at a temperature above freezing or the frost point temperature when the change of state occurs at a temperature below freezing. Whether dew or frost will form is determined by two factors: 1  If the amount of moisture in the air causes the condensation temperature to be above or below freezing and. 2  If the temperature will cool to the condensation t (Note that the water vapor goes directly from gas to ice. Therefore, frost is not frozen dew.). Thus, if the temperature on the ground or an object such as a bush or a car windshield near the ground falls below the frost point, frost crystals may form. But the measured  surface temperature  may still be above freezing. Now frost is a covering of ice crystals on the surface produced by the depositing of water vapor to a surface cooler than 0° C (32° F). The deposition occurs when the temperature of the surface falls below the frost point. Similarly, dew forms when the air or surface temperature falls below the dew point temperature. Thus, if the temperature on the ground or an object such as a bush or a car windshield near the ground falls below the frost point, frost crystals may form. But the measured  surface temperature  may still be above freezing. Frost or freezing occurs when the temperature of air falls below the freezing point of water (0 °C, 32 °F, 273.15 K). This is usually measured at the height of 1.2 m above the ground surface. There is a rather subjective scale to show several degrees of frost severity: 1  slight frost: 0 to −3.5 °C (32.0 to 25.7 °F). 2  moderate frost: −3.6 to −6.5 °C (25.6 to 20.3 °F). 3  severe frost: −6.6 to −11.5 °C (20.2 to 11.3 °F). Frost. Frost is a form of ice and can only survive at temperatures of 32 degrees Fahrenheit and below. But that doesn’t mean the measured air temperature must be 32 or below for frost to form on a surface. Frost may occur overnight, but it often forms at sunrise, before the temperature begins to rise. Frost formation on grass is possible in any location in which the blades’ temperature falls to 32 or below, including warm weather states such as Florida, California and Arizona. A light frost occurs when the temperature drops to below 32 degrees Fahrenheit, and refers to the conditions that allow a layer of ice crystals to form when water vapor condenses and freezes without first becoming dew. 1 Harvest basil and other tender herbs before a light frost (when the temperature drops to 32 degrees Fahrenheit). 2  Even if they survive the frost, they don't do well in cold temperatures. 3  The same is true for most annuals. 4  Bring geraniums indoors before the first light frost arrives. The ease of locating a Temp-Frost equipment from supermarkets, restaurants, pubs, hotels, schools, clubs, convenience store, coffee shops, food courts, five-foot ways of HDB blocks, hawker centres and even wet markets, is testimony to the trust customers have in our equipment. Set up in 1992, Temp-Frost has established itself as a market leader in the field of refrigerated equipment and are specialists in the supply, maintenance and total management of the valuable assets belonging to many reputable brands and companies in Singapore.
https://en.wikipedia.org/wiki/Frost http://www.shorstmeyer.com/wxfaqs/frost/frost.html http://www.islandnet.com/%7Esee/weather/whys/frost.htm http://www.islandnet.com/%7Esee/weather/whys/frost.htm https://en.wikipedia.org/wiki/Frost_(temperature) http://golftips.golfsmith.com/temperature-frost-form-golf-course-20714.html http://www.almanac.com/blog/editors-musings/blog-how-predict-frost http://tempfrost.com/
what temp is frost