The Macchie of the Neapolitan Coast Region

Abstract

The general character of the Neapolitan climate, with its mild moist winters and long dry summers, has been mentioned in a previous article. The irregular distribution of the mountains along the coast of the Bay of Naples and upon its islands produces considerable inequalities in the rainfall of localities not widely separated. In Capri, during the summer in which I was engaged in studying its flora (I902), the precipitation was less than usual, 45 mm in May, ending on the twentieth, and then a rainless period of four months, except for a shower of 6mm on September 13. During a more nearly average year (i 90 i) the precipitation for May was I79mm, June and July 56 5mm, August none, and September 97.2 mm. During the three hot, dry months (June, July, August) the nights are usually moderately cool. In 1902 the minimum for the three months was io.80 C. The maximum for the same period, measured under strictly standard conditions, was 31.90 C. The average of daily maximum temperatures for June, July, and August was 26.4? C. It is noteworthy that the heat is continuous, the maximum of each day usually differing less than 2? from that of the day before or the following day. The desiccating effect of hot air upon vegetation is, of course, largely dependent upon the relative humidity of the atmosphere. During June, July, and August, I902, the relative humidity at 3 P. M. never exceeded 8i and not infrequently fell to 30 or less; once as low as 27. The average relative humidity at 3 P. M., for the three months in question, was 55. The average velocity of the wind in summer at 3 P. M. was about 9km per hour.