2025 solar performance exceeded expectations in many key markets
Solargis, the industry’s trusted source for solar data and software, has published its annual solar irradiance analysis for 2025, revealing how solar irradiance levels deviated from expectations across the globe. The data shows that global solar irradiance reached both positive and negative extremes last year, with the highest positive anomalies reaching up to 20% above long-term averages.
Solargis’ 2025 Global Solar Performance maps cross reference 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.
2025 marked a record year for renewables, with over 800GW capacity being added globally. Solar power has been responsible for almost 80% of the total renewable capacity increase, demonstrating that the world has never been more reliant on solar as a key part of the global energy mix.
Solargis’ latest annual solar irradiance analysis for 2025 shows that this global increase in solar power production was supported by above-average solar irradiance across a number of energy-producing markets.
Throughout 2025, Southeast Australia and New Zealand saw typical GHI values in a range of 3% to 10% higher than the regional long-term averages. However, the highest difference in the Australasian region were on New Britain and New Ireland islands belonging to Papua New Guinea, where irradiance levels often exceeded 15% above LTA.
Europe generally benefitted from a higher-than-average solar irradiance, although levels varied across the continent. Notably, the UK had its sunniest year on record ever and Solargis’ data shows that many localities In the UK and Benelux countries experienced irradiance 10% above LTA. Similarly, in most of West and Central-Southeast Europe, irradiance was 4-10% higher than normal.
The region of East Asia, particularly Central East China and parts of the Sichuan Basin stand out in 2025. Central East China recorded +15% above the long-term norm, with parts of the Sichuan Basin reaching +20%. This continues a multi-year trend: the last four to five years have all been above average, making 2025 another exceptional chapter for PV operators in these provinces. Neighbouring countries also experienced a strong year. Japan and the eastern coastal regions of South Korea saw widespread anomalies of +4% to +10%, supporting above-expected PV output at many sites.
Marcel Suri, CEO & Founder, Solargis, said: “2025 has been a watershed year for the renewable energy industry and one that fills us with hope for the future, especially with solar power at the forefront of this impressive growth. We expect reliance on solar power to continue growing into 2026 and beyond, so it will be more important than ever to invest in the data required to understand it.”
“Our analysis shows that the last year was one of extremes for solar irradiance levels: some regions experienced significantly above average levels, while others had much lower GHI than usual.”
“Solar has attracted both positive and negative headlines in 2025 as its role in global power grids has been scrutinised, and it has never been more important for the industry to arm itself with the right data and software to closely monitor solar resource variability patterns and take steps to protect assets accordingly.”
The Ongoing Challenge of Extreme Weather
Despite positive news from some key markets, Solargis’ results also show that extreme weather, including above average rainfall, hurricanes and floods in certain regions continued to impact the industry - causing significant dips in GHI levels in countries like India, Nicaragua or Vietnam.
In a year with fewer extreme weather events than previous ones, the US, Canada and Mexico saw stable solar performance. This trend, however, wasn’t mirrored in Central America – notably Panama, Costa Rica and Nicaragua. The region experienced an overall dip in solar irradiance due to a stronger than average hurricane season in the second half of the year, which featured increased rainfall. The results were GHI levels 7% to 12% lower than average.
In 2025 India had its second consecutive year of above-normal monsoons, with the season ending with a 108% increase on the long-period average rainfall. As a result, most of India continued to experience below average irradiance levels, ranging between –1% to –8%, with regions along the southwest coast dipping down to -10%.
In Southeast Asia, the 2025 rainy season was strengthened by a strong La Niña weather phenomenon in some parts of the region. This caused heavy floods as well as a decrease in solar irradiance in a range –5% to –8% around Central Vietnam, Northwest Malaysia and other surrounding islands. Vietnam in particular suffered intense storms and record-breaking rainfall levels during the months of September and November, which caused widespread disruption in the solar power industry and beyond.
Most of the African continent had stable solar irradiation levels, however in the Johannesburg-Pretoria region of South Africa GHI levels reached -8% below LTA.
Suri added: “With the La Niña phenomenon expected to persist for the rest of this winter season, we will likely see its effects exacerbate extreme weather events in certain regions. Extreme rainfall, floods and hurricanes present significant risks to solar projects in these regions, which asset managers need to plan ahead for if they want to keep their projects profitable in the near future.”
