By 14,500 BP, an increase in summertime solar radiation and the resulting retreat of the glacial sheets began to change the climate of North America. The whole of North America did not experience a universal change at once, rather, various regions experienced different rates of change depending on the region. Between 14,000 BP and 11,000 BP temperatures in the Paleoindian Northwest Alabama were cooler than present temperatures and the percentage of precipitation the region experienced was significantly higher than present (2,000 mm vs the present 1,250 mm today), probably due in part to higher winter precipitation.
Temperatures increased over the course of the next 2,000 years, while precipitation decreased significantly to present day percentages as North America transitioned from the Pleistocene to Holocene period. The Early Archaic period coincides with the onset of the Holocene period, marked by warmer climatic conditions resulting in changes in vegetation, fauna, and seasonal temperatures. While temperatures in Muscle Shoals temperatures experienced little change, there were significant, differences between summer and winter temperatures by the end of the early Archaic Period.