Warm Season South America Precipitation during El Nino: Wetter. Discussion: From a MARKET perspective, especially in agriculture, the influence of El Nino on precipitation has traditionally been recognized as observed by the titanic El Nino episodes of 1982-83 and 1997-98. El Nino 1982-83 and to a lesser extent 1997-98 occurred when global oceans were much cooler than they are now, the polar ice cap was more expansive and CO2 emissions were climbing but nowhere near values observed since 2000. Cycles identifying ocean thermal regimes as defined by El Nino southern oscillation (ENSO), Pacific decadal oscillation (PDO) and Atlantic multi-decadal oscillation (AMO) each changed phase in the late 1990’s along with the sharper increase in CO2 levels. Reasonable is the question of whether El Nino/La Nina historical climate regimes changed. A look at warm season rainfall across South America based on 3 El Nino episodes occurring since the 1997-98 El Nino (when the global oceans warmed, polar cap shrunk and ENSO/PDO/AMO long-term cycles changed) and 3 El Nino episodes just prior to that time including 1997-98 are reviewed. The clear trend with the more modern day El Nino climate is a somewhat wetter warm season regime across southwest and southeast Brazil to northeast Argentina. Dryness in central/northern Brazil tends to be stronger with post 1997-98 El Nino episodes. The wetter trend is likely related to a much warmer tropical North Atlantic in the post 1997-98 El Nino’s. In 2018 El Nino is developing with a warmer than normal tropical Atlantic. New (top) Versus Old (bottom) El Nino Precipitation OCT/NOV/DEC OCT/NOV/DEC discussion: Post 1997-98 El Nino’s are drier across Brazil and wetter in Southeast Brazil/Uruguay compared to earlier El Nino episodes. Thematically similar precipitation character but post 1997-98 El Nino’s are more extreme. New (top) Versus Old (bottom) El Nino Precipitation DEC/JAN/FEB DEC/JAN/FEB discussion: Meteorological summer is wetter Paraguay/Southeast Brazil/northeast Argentina during post 1997-98 El Nino’s compared to earlier El Nino episodes. Central and northern Brazil are drier with recent El Nino episodes. New (top) Versus Old (bottom) El Nino Precipitation JAN/FEB/MAR JAN/FEB/MAR discussion: During quarter 1 of the year the post 1997-98 El Nino events are wetter in Southeast Brazil to northeast Argentina.