The variation over the year is a direct consequence of the precipitation regime, i.e., the maximums occur in summer and the minimums in winter (Buitrago and Larrán, op cit.).In addition to the precipitation regime, temperature is an incident factor.In monsoon systems like the one that characterises the region, maximum relative humidity occurs in the autumn months due to the lower temperature compared to summer and the high humidity that remains after rainfall (Buitrago and Larrán, op cit, Soler, 2003).