Climate and Best Time for a visit:
The climate is warm and dry, with few rains - 700 mm a year - in summer, from December to March. In the cities of Salta and San Salvador of Jujuy, temperature varies between the 20º C and 27º C and the minimum between 5 and 15 C.
In La Quiaca the temperatures vary between 15 C and 20 C and the minimum is between -5 C and 7 C, with practically no rain.

Climate in Salta
Climate in Jujuy
Climate in La Quiaca