This master thesis investigates the design and implementation of a physical daylight simulationlab within the architecture building at KTH. The primary objective is to replicate diffuse skylightwith its natural conditions using artificial lighting systems, guided by the prevalent CIE sky typemodels. Utilizing the Radiance software suite, the study models complex lighting scenarios andevaluates various sky conditions, such as clear, overcast, uniform, and partly cloudy skies. Byintegrating the Tregenza subdivision method, the sky dome is divided into 145 patches, eachcontributing to the overall light distribution in the simulation. This approach allows for precisecontrol and adjustment of luminance levels and spectral qualities for each patch, ensuring realisticdaylight conditions. The research includes theoretical studies, practical experiments, and casestudies, emphasizing the importance of diffuse skylight and the spectral qualities of natural light.This work aims to enhance both educational and professional practices for architects and inarchitectural lighting design by providing a controlled environment for studying the impact ofdaylight on architectural models. In parallel, a collaboration with Harsh Indurkar focuses on thesimulation of direct sunlight in his separate thesis, Daylight Simulation Lab: Mapping andImplementing Temporal Variation of Sunlight (Indurkar, 2024). This collaboration ensures acomprehensive understanding of natural light dynamics, complementing the design of the daylightsimulation lab at KTH, the Royal Institute of Technology in Stockholm, Sweden.