The present study is concerned with the spatial variation of the frost thickness as well as the pattern of the frost crystals formed on a cold plate in atmospheric air. Experimental results regarding the two-dimensional variation of the frost thickness at the leading edge and observation on the growth of the frost crystals on the frost formation are provided. A microscopic image system is used to observe the structure of the frost layer. The environmental variables considered in this study include the velocity, temperature, and relative humidity of the air (V, T-a, and phi), as well as the surface temperature of the cold plate (T-w), which is varied by adjusting the cooling refrigerant temperature (T-ref). The ranges of the physical variables considered in this study are 2 less than or equal to V less than or equal to 8 m/s, 18 less than or equal to T-a less than or equal to 30 degreesC, 40%, less than or equal to phi less than or equal to 70%, -18 less than or equal to T-ref (and T-w) less than or equal to 0 degreesC.