The weather conditions, the tropic of Capricorn which divides the province into two halves, the average altitude of the regions and the topography make the contrast in the climate of the province. It varies from the glazier cold of the Altiplane to the warm climate of the Quebrada de Humahuaca or the tropical of the valleys from the San Francisco river. In summer, in the same day, the temperature may be 45º and 25º centigrade while at sunset the temperatures may be below zero in the region of the Altiplane and the highest mountains.
The Altitude of the Puna marks a cold and dry climate most of the year, while the passes and valleys have a better climate. The tropical climate is typical of the San Francisco valley and the neighboring regions. The average rainfalls reach the 900 mm a year.