In this paper, we propose a new calculation method for evaluating the inhomogeneous outdoor thermal environment by incorporating a multi-node human thermoregulation model into the simulation method based on CFD analysis of the outdoor thermal environment. We also investigated the effects of weather conditions on the inhomogeneity of the radiant environment for pedestrians using the proposed calculation method. Two different weather condition cases are investigated in this study: (1) a scorching hot day and (2) a cloudy day. The analysis confirmed the effectiveness of the proposed method in the evaluation of the inhomogeneity of the radiant environment in outdoor space.