Mississippi River Basin Evaporation in Average Year

On an annual basis the North West corner of the Mississippi basin has low levels of evaporation and as you travel to the south east the evaporation increases. This is not surprising as rainfall near the river mouth is greater than in the western portion of the basin. For the months January to March there is a clear division between the northern cooler climates and warmer southern locations where evaporation is maintained even during winter. From April onwards there is increased evaporation through the entire basin with the summer months (June-July) experiencing maximum levels of evaporation. September to December there is a progressive reduction in evaporation from the NW corner to the mouth of the Mississippi.