Central East China records 15% above long-term norm of solar irradiance

Central East China recorded a 15% rise, Japan and South Korea 4% and 10%, respectively.

The East Asia region continued to record increases in solar irradiance, with Central East China recording +15% above the long-term norm for solar irradiance and parts of the Sichuan Basin reaching above 20%.

In its annual solar irradiance analysis, Solargis also found Japan and the South Korea eastern coastal regions saw widespread anomalies of plus 4% to 10%, supporting above-expected PV output at many sites.

Solargis said that solar irradiance levels in the region had recorded above-average growth in the last four to five years.

The report reveals how solar irradiance levels deviated from expectations across the globe, it said in its 2025 Global Solar Performance maps. It said that the maps cross-referenced satellite data on Global Horizontal Irradiation (GHI) from the past 12 months with long-term averages (LTA) to show how the performance of solar projects may have deviated from expectations.

Southeast Australia and New Zealand saw typical GHI values in a range of 3% to 10% higher than the regional LTA.

However, the highest differences in the Australasian region were seen in New Britain and New Ireland islands belonging to Papua New Guinea, where irradiance levels often exceeded 15% above LTA, it added. 

Across the globe, its findings showed that solar irradiance reached both positive and negative extremes last year, with the highest positive anomalies reaching up to 20% above long-term averages.

The year 2025 also marked a record year for renewables, with over 800GW capacity being added globally, it said.

Solar power has been responsible for almost 80% of the total renewable capacity increase, showing that the world has been more reliant on solar as a key part of the global energy mix, it added.