Fugten i luften kondenseres, når den kraftige vind fra Det Tyrrheniske Hav blæser hen over kystsletten og op over de stejle bjerge; dette giver en hyppig og kraftig nedbør.
Strong currents of wet air from the Tyrrhenian slope, after crossing the short coastal plain, immediately condense as they are forced upward by the mountain chain, creating high levels of precipitation, increasingly frequent and intense the further one moves over the marble-bearing spurs.