In a new weekly update for pv magazineSolcast, a DNV company, reports that April 2026 brought mixed solar radiation across South America, with an above-average GHI along the Pacific and Caribbean coasts of Colombia and parts of southern Argentina, while the eastern and northern temperate regions – from Buenos Aires to Bolivia – experienced reduced insolation due to persistent cloud cover and wetter than average conditions.
April 2026 produced sharply contrasting solar radiation results across South America, with gains along parts of the northern coastline and southern Argentina offset by notable declines in the eastern and northern temperate regions, according to analysis using the Solcast API. These patterns closely matched cloud and precipitation anomalies typical of an ENSO-neutral to El Niño transition, producing regionally divergent responses rather than a continent-wide signal.
Across northern South America, there were clear positive surface radiation anomalies along both the Pacific and Caribbean coasts of Colombia in April. The GHI anomaly map shows values about 10-20% above the 2007-2025 average, consistent with reduced cloud formation along coastal areas. This pattern is characteristic of ENSO transition periods, during which atmospheric circulation becomes more variable and convection moves away from some coastal areas. An article from the NOAA Climate Prediction Center, released on April 9, 2026, confirmed that conditions shifted from ENSO neutral to El Niño, a phase known to disrupt typical cloud and rainfall distributions rather than uniformly strengthening tropical convection. During these transition seasons, localized reductions in cloud cover may occur, increasing solar performance despite future uncertainty.
In contrast, the region from Buenos Aires to Bolivia experienced suppressed insolation through April, caused by wetter than average conditions and persistent cloud cover. Reports of uneven but increased rainfall along the southern Brazilian coast and northern Argentina indicate persistent cloud fields that limited solar energy production. This coastal belt is particularly sensitive to cloud-induced reductions in insolation during wetter periods because sea moisture and overland flow can maintain extensive low- and mid-level clouds. While this suppression dominated the extreme south of Brazil, the northern and parts of the northeastern Brazilian coastal segments showed more mixed conditions, with locally positive or near neutral GHI anomalies despite the broader southern downturn.
Argentina showed an inverse pattern, with northern regions experiencing radiation suppression while southern regions fared relatively better. Climate monitoring for April 2026 indicates that precipitation totals in Buenos Aires and northeastern Argentina are well above normal, with associated cloud cover limiting solar radiation. Research shows that in ENSO patterns like we are in now, these phases can systematically reduce insolation in northern Argentina while leaving southern regions largely unaffected or even slightly enhanced, consistent with the pattern we saw in April.
Solcast produces these figures by tracking clouds and aerosols worldwide at a resolution of 1-2 km, using proprietary satellite data AI/ML algorithms. This data is used to drive irradiance models, allowing Solcast to calculate high-resolution irradiance, with a typical deviation of less than 2%, as well as cloud tracking predictions. This data is used by more than 350 companies that manage more than 300 GW of solar energy worldwide.
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