Executive Summary: The Climate Impact Company season 1-4 ahead climate forecast for South America is updated. The forecast is valid for meteorological autumn 2024 through summer 2024-25. The forecast is based on an optimum climate normal (OCN) and complete shift in the ENSO regime plus cooling of the tropical South Atlantic waters. The high profile highlights include a continuing Brazil drought which worsens next summer and freeze potential for Brazil in June and monitoring for another cold event in July. South America summer 2023-24 verification: The warmest nearby tropical SSTA pattern on record was observed during meteorological summer 2023-24 to help shape the South America climate. The axis of strongest convection propelling the intra-tropical convergence zone (ITCZ) stretched across the warm El Nino waters in the tropical East Pacific toward Northern Peru and across the historic warm tropical South Atlantic (TSA) index measurement area from the equator to 20S in the South Atlantic (Fig. 1). The latent heat release poleward from the ITCZ convection caused warming of the subtropical to mid-latitude atmosphere either side of South America inspiring strong subtropical high-pressure areas over Northern Chile and off the East Coast of Argentina (Fig. 2). The sensible weather created by the ITCZ, and subtropical high-pressure combination yielded below normal rainfall across Central and South Brazil causing a drought compensated by enough rainfall in Argentina to ease drought while East Brazil was soaking wet (Fig. 3). All of Brazil and Northern Argentina was hotter than normal (Fig. 4). Fig. 1-4: Global SSTA analysis for DEC/JAN/FEB 2023-24, where the ITCZ set-up and the compensating subtropical high-pressure areas, and the sensible temperature/precipitation anomalies for meteorological summer 2023-24. The Climate Impact Company DEC/JAN/FEB 2023-24 temperature and precipitation forecast for South America projected a much hotter than normal summer for Brazil into Northeast Argentina (Fig. 5) while the rainfall outlook called for North and Central Brazil drought while parts of Interior Southeast Brazil and Argentina were wetter than normal (Fig. 6). The observed thermal climate was a close match to the forecast featuring widespread anomalous heat (Fig. 7). The rainfall verification validates the Central Brazil and coastal Southeast Brazil dryness although the forecast was too wet near Paraguay but correct with wet climate in East Brazil (Fig. 8). Fig. 5-8: The Climate Impact Company DEC/JAN/FEB 2023-24 temperature/precipitation anomaly forecast compared to verification. Climate 2024-25 discussion: Will the very warm tropical SSTA pattern continue? The 2023-24 El Nino has peaked, matured, and is now weakening fast as subsurface waters in the equatorial East Pacific to the east of the Dateline cool rapidly. The Climate Impact Company Nino34 SSTA constructed analog forecast indicates neutral ENSO within 2-3 months and a reversal of ENSO phase to La Nina by JUL/AUG 2024 (Fig. 9). La Nina strengthens later this year. The latest NMME global SSTA forecast for AUG/SEP/OCT 2024 indicates a dramatic change in the tropics lead by moderate (or stronger) La Nina, a reversal in the IOD pattern, and dissipation of the historical +TSA regime (Fig. 10). Similar with other climate forecasts issued by Climate Impact Company, an optimum climate normal (OCN) is applied to the climate forecast which recognizes the short-term climate pattern due to the increased warming of the mid-latitude oceans of the past 10 years. The South America climate outlook through next summer is based on an ENSO transition from El Nino to La Nina, a shift in the IOD pattern, cooling of the South Atlantic tropics, and the OCN. Fig. 9-10: The Climate Impact Company Nino34 SSTA constructed forecast reveals La Nina by JUL/AUG intensifying later this year while the global SSTA projection by NMME identifies a complete change in the global tropics. MAR/APR/MAY 2024: The meteorological autumn 2024 outlook is remarkably consistent featuring additional dryness to maintain the Brazil drought (which expands eastward). Wet weather is focused on Northeast Argentina, Southeast Brazil, and Paraguay. Cool weather risk remains confidently forecast across Argentina while much of Brazil stays warmer than normal during autumn. Fig. 11-12: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for MAR/APR/MAY 2024. JUN/JUL/AUG 2024: During the meteorological winter season the greatest risk of a freeze to Brazil coffee growing areas is in June. However, the primary catalyst to a mid-winter Brazil freeze risk is the Amundsen Sea low pressure area southwest of South America which is intense and reaching Chile. If this feature extends farther northward, which is not indicated now, a major freeze could occur in Brazil. Consequently, the mid-winter forecast is precarious. The winter outlook is warm across the northern 2/3 of Brazil and seasonably dry with a cooler trend indicated for Argentina. Fig. 13-14: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for JUN/JUL/AUG 2024. SEP/OCT/NOV 2024: The meteorological spring 2024 outlook maintains a warmer than normal regime across Brazil while a lingering cooler than normal climate is maintained across Argentina. Dryness is projected across Western Brazil and Northeast Argentina and each projection is a drier change. Heading into summer 2024-25, Brazil drought continues. Fig. 15-16: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for SEP/OCT/NOV 2024. DEC/JAN/FEB 2024-25: The meteorological summer 2024-25 season yields dryness across Central and Southeast Brazil. If so, a major drought occurs in these areas due to long-term rainfall deficits for much of this region. The outlook is likely hotter than indicated for Brazil. If Brazil is as dry as projected, Argentina dryness is not as strong. The forecast trend is drier expanse for Brazil. Fig. 17-18: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for DEC/JAN/FEB 2024-25.