The purpose of this study is validating the factors which affect the surface temperature of a cuboid under transient solar irradiance. The surface temperature is determined by considering the material property and weather conditions including the solar irradiance which plays a major role in thermal signature profile in clear daytime. This study focuses on verifying the unsteady temperature prediction result obtained from a SW developed in this study by comparing with those results obtained from a commercial SW and measurement. In this paper, a cuboid on reflecting platforms with different surface reflectivity is used for verifying the measured and calculated temperatures by considering a diurnal variation of climatic changes. The developed SW predicts the surface temperature of the cuboid considering the real-time weather data from measurements. From this study it is observed that the developed SW is compared fairly well with the commercial SW RadThermIR, and the developed SW shoes better agreements with the measured data as compared to the RadThermIR data. We also found that the use of proper radiative surface properties is very important to obtain more accurate modeled results especially for highly reflecting system with solar irradiation.