It is observed that the cooling capacity of impinging water jet is affected by the seasonal conditions in steel manufacturing process with large scale. To confirm this phenomena, the cooling experiments of a hot steel plate by a laminar jet were conducted for two different initial ambient air temperature($10^{circ}C$ and $40^{circ}C$) in a closed chamber, and an inverse heat conduction method is applied for the quantitative comparison. It is found that the cooling capacity under $10^{circ}C$ air temperature is lower than that under $40^{circ}C$, as is the saturated water vapor is more easily observed, and the amount of total extracted heat in the case of $10^{circ}C$ is smaller by nearly 15% than that of $40^{circ}C$ case. From these results, it is thought that the quantity of water vapor, which could be absorbed until saturation, effects on the mechanism of boiling heat transfer.