The plateau characterizes by the abrupt thermal oscillations and the little precipitations, that not very often surpass 200mm annual. To these conditions it must to the desolation of this region, populated so single with handfuls of the grass puneño that serves as food the guanacos, the flames and the vicunas. A marked resistance is observed in valleys, the gorges and the Andean mountain ranges with a more benign climate, responding to a mountain tropical climate. The capital salteña constitutes an example of it with summer averages that surpass 20° C and inferior winter averages to 14° C. In summer the principles are used to surpassing 38° C, as well as in winter the temperature descends below cero to several degrees.