South America sees strong solar gains despite weak La Niña conditions

South America saw widespread above-average irradiance in January, despite weak La Niña conditions. However, storm systems fueled by Atlantic moisture suppressed solar generation in parts of Brazil and Bolivia. Irradiance ranged from up to 15% above average in most regions to 10% below average in storm-affected areas.

January 2025 was favorable for PV production across much of South America, with irradiance 5-15% above average. This observation contrasted with typical weak La Niña conditions, which usually do not bring such widespread increases in irradiance. 

While some modelling agencies have declared La Niña conditions for January, supported by Pacific sea surface temperatures that meet La Niña thresholds, historical data shows weak events rarely drive such increases in irradiance. Compared to similar ENSO years, January 2025 saw higher irradiance anomalies, particularly in the western and southern parts of the continent. This aligns with earlier forecasts predicting a bright summer season in the region. Moreover, record warm global sea surface temperatures, an ongoing indicator of climate change, may be influencing and altering the typical impacts of La Niña.

However, not all of South America benefited from these trends. Parts of Brazil and Bolivia saw irradiance levels dip 5-10% below average due to stormy weather and associated cloud cover. These conditions were driven by stronger-than-usual trade winds, which carried abundant moisture from the anomalously warm Atlantic Ocean into the region. The resulting heavy rainfall led to widespread flooding and landslides, particularly in southeastern Brazil and Bolivia.

These disruptive rainfall events and associated irradiance impacts highlight the challenge of predicting solar conditions in a variable tropical summer climate. La Niña and climate change add to the complexity of the task.

Track weather conditions, cloud movements, and irradiance-influencing factors that impact your solar generation. Access bankable actuals and accurate forecasts when you sign up for a Solcast API toolkit. You can reach out to our team for an extended trial.