A method for selecting the CIE standard general sky model with regard to calculating luminance distributions

► Sky luminance measurements were compared with three calculation models. ► Best predictions are obtained by the CIE 15 skies model. ► The CIE 15 skies model is applicable only when sky luminances are measured. ► A new way of applying the CIE 15 skies model, called CIE-Si is proposed.