• • Annual global solar radiation increased at +7.03 MJ/m² per decade over 1961–2023, with a mean of 5946.57 MJ/m² and a maximum of 7333.62 MJ/m² in 2017; this sustained upward trend underpins long-term bankability for utility-scale solar deployment in the region.
• • Mann-Kendall change-point analysis reveals a significant decline of −364.01 MJ/m² per decade during 1961–1986 (α = 0.01), reversing to a significant increase of +147.55 MJ/m² per decade during 1987–2023 (α = 0.05); this regime shift invalidates stationarity assumptions in historical resource assessments and requires time-dependent yield modeling.
• • Seasonal radiation partitioning is summer 33%, spring 29%, autumn 23%, and winter 15%, with spring exhibiting the strongest upward trend at +23.66 MJ/m² per decade (α = 0.05) while autumn and winter decline at −10.33 and −9.37 MJ/m² per decade, respectively (not significant); this asymmetry affects seasonal storage sizing and maintenance scheduling.
• • Precipitation, overcast, and cloudy conditions cause the most severe attenuation of global solar radiation, whereas clear and partly cloudy skies dominate the annual energy budget; accurate cloud-cover classification is therefore critical for intra-day power forecasting and grid integration.