Evaluation of six sky luminance prediction models using measured data from Singapore

Measured sky luminance distribution data are being collected in Singapore as a part of the International Daylighting Measurement Programme (IDMP) of the Commission Internationale de l'Eclairage (CIE). These data have been used to evaluate six different sky luminance distribution prediction models developed in recent years. The majority of the models have been shown to work satisfactorily, though they have a tendency to overestimate the sky luminance, especially in the regions of the sky farther away from the sun.