The climate of the Andes is very interesting. Most of the areas enjoy a mild tropical climate.The northern Andes are made up of three mountain ranges that spread out to catch and keep the moisture of the northeastern trade winds. This in turn gives a large amount of rainfall to the area.
On the Pacific side of the mountain range, from the Isthmus of Panama to the equator, the Colombian Andes catch the southwardly winds, leading to rainfall almost every day. Argentina's eastern slopes are relatively dry.
The region from the Gulf of Guayaquil through the Northern part of Chile (the west coast) is very arid. This stretch of land lies in the path of the trade winds. There the winds tend to come from the east and the southeast and drop the moisture level of the eastern slopes of the Andes.
In Valparaiso, the western coast has a Mediterranean-type climate which has drying trade winds in the summer and moisture-laden winds in the winter.
Down south, westerly winds come throughout the year. Chilean slopes of the Andes catch their moisture as drenching heavy weather such as rain or snow.