Puelche, puihua, raco or terral is the name given in the central and southern areas of Chile, a sporadic and strong easterly wind coming from the Andes Mountains and blowing towards the Chilean valleys, where they become warmer as they descend.[1]​.

The word "puelche" comes from Mapudungun, the language of the Mapuche people, it means "people of the east", and was used to designate several peoples who lived east of the Andes, among them the self-named gününa küne, who in Spanish are those who usually receive the designation of puelches.

It is a katabatic wind, that is, it originates from a cooling of air at the highest point of the Andean valleys. As the density of the air increases with the decrease in temperature, the air will flow downwards, warming by an adiabatic process as it descends, that is, when the cold air at its origin densifies, it lowers and compresses, so its temperature increases and the locals feel a pleasant warm breeze. The geography of the central area prevents this wind from reaching too much speed or danger, however, in the south of Chile it can cause roofs to blow off and trees to fall, as occurs in other cases in the world, for example in:

• - Zonda in Argentina.

• - Chinook "Chinook (wind)") in Canada and the United States.

• - Surada or Ábrego, Terral in Spain.

• - Foehn or Föhn in Germany.

However, given that the southern part of Chile is an area that has had a great development of the logging industry in the last decades of the century, puelche has come to be perceived as dangerous due to the possibility of forest fires mainly in the summer.

• - In the Maipo valley where Santiago is located, it is called "Raco" because it apparently comes from that premountain area of ​​the Maipo River. It is a warm and pleasant breeze on winter mornings. Its low predictability makes it unusable since the trade winds typical of the area always go in the opposite direction.