New Caledonia experiences a decrease in surface solar irradiation since 2004. It is of order of 4 % of the mean yearly irradiation over the 10 years period: 2004–2013, and amounts to −9 W m−2 . The preeminent roles of the changes in cloud cover and to a lesser extent, those in aerosol optical depth on the decrease in yearly irradiation are evidenced. The study highlights the role of data sets offering a worldwide coverage in under-standing changes in solar radiation and planning large solar energy plants such as the ICOADS (International Comprehensive Ocean-Atmosphere Data Set) of the NOAA and MACC (Monitoring Atmosphere Composition and Climate) data sets combined with the McClear model.