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San
Juan is geomorphologically structured by a series
of mountain ranges, most of them with a North-South
direction from different geological times. Among them
there are low areas or flat longitudinal valleys formes by
modern sediments. Two third parts of San Juan
relief are mointainous. To the West, the peaks of Los Andes
Cordillera eternally covered with snow can be seen.
Among these heights longitudinal valleys appear and Pre-
cordillera continues from North to South. The Western border of
these heights allow the union of the waters
which come down from the Main and Front cordilleras giving rise to Jachal
and San Juan rivers. These allow the
formation of oasis, where fruit, viticultural
and horticultural activities are developed, which constitute valuable
sources of production. In fact, through
the nutritious water of San Juan River,
our vineyards receive the
necessary irrigation to yield an excellent product.
San
Juan climate is arid and dry. We have four seasons. The damp
winds from the Pacific and Atlantic Oceans
hardly get to this region. The ones coming from
the Atlantic meet in their way several obstacles to
produce
precipitations and they do not arrive here
because of the great distance they have to go through
from their
original place. The winds from the Pacific have to overcome the huge barrier
of the Cordillera.
Zonda
Wind
A mass of cold air charged with humidity originates in
the Pacific Ocean which goes up Los Andes
peaks
reaching -12ºC. At that point, humidity is lost
in the form of snow and it goes down at great speed towards the
valley. This speed and the friction
against the mountainside warmed by the sun give this
extremely dry its
typical high temperature. Having unloaded its
humidity in the Cordillera, it is a very dry wind which raises the
tamperature and lowers the ambient humidity. It speeds up fruit ripening.
It blows in any season of the year. The
snow it leaves in the Cordillera enriches the glaciers which produce greater
water flows in the rivers which fill the
dams and whose water is partly used for agriculture. Zonda wind is cleared
by South wind.
South
Wind
The winds from the south blow during the whole year.
North
Wind
It
often blows. It carries humid and warm tropical
air. These winds cause temperature changes mainly, but in
most of the cases they do not even reach the average speed.
 
Rainfalls
Precipitations are rare. The annual number of
pluvial precipitations is very low. Dureing the winter,
frost are
abundant and the weather is generally cold.
Temperature
It is very hot and there is
a marked variation between day and night temperatures. The nicest
seasons are
Autumn and Spring. The maximum temperatures
recorded in the province surpass 45ºC un Summer and the
minimum ones -6ºC in winter.
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