In order to study safety in refuge spaces and measures for preventing the spread of urban fires, it is important to predict the temperature distributions in thermal plumes generated by the fires. The objective of this study is to acquire knowledge of temperature distributions in fire-induced flows to serve as a base for the research. In past studies by the authors, their derived relational expressions for temperature distributions in thermal plumes under windy conditions treated the fire region, such as a burning house, as a square heat source through a series of wind tunnel experiments simulating urban fire scenarios. This paper describes a study on the above by larger-scale experiments for the expressions generally used.