This study explores how climate varied across Patagonia, Argentina, about 100 million years ago, during a very warm period in Earth’s history. We analyzed ancient soils (paleosols) from four regions, stretching from north to south, to understand past temperature and rainfall patterns. The results show a clear climate gradient: drier in the north and wetter in the south. These ancient soils reveal that Patagonia was much more humid in the past than it is today. The findings suggest that warm periods in Earth’s history caused changes in wind and rainfall patterns, expanding warm, moist conditions toward the poles. This helps scientists better understand how past climates worked and what changes we might expect in the future as the planet warms again.