Frostpoint temperature T f is the temperature at which the water vapour contained in a gas starts to form frost when cooled

霜點溫度是氣體中包含的 水蒸汽開始結霜時的溫度 or 或者

Frostpoint is defined as the temperature at which a moist gas is saturated with respect to a plane surface of pure ice

霜點是濕氣體達到飽和 狀態并在平面表面產生純冰時的溫度