Three zones of climate are distinctly marked. The tierra caliente, or hot land, lies along the low maritime zone of the Gulf and the Pacific, and includes swampy and sandy coast lands and well-watered plains and slopes leading up to the mountains. The growth of luxuriant tropical vegetation is promoted by a mean annual tem perature of 77° to 82° F., the mercury seldom falling below 00°, but often rising to 100°, and in the sultry di.stricts of Vera Cruz and Acapulco to 104°. Some places, as the port of La Paz, are among the hottest in the world. The sea coasts are unhealthful, fevers prevail. and in some localities yellow fever and black vomit are endemic. The health conditions may be greatly improved by draining the swamps, as has already been shown at Vera Cruz.
Above the Gulf and Pacific hot zones are the sierras templadas, or temperate lands, from 3000 to 0000 feet above the sea, embracing the higher terraces and parts of the central plateau. The temperate lands rise to a higher elevation in the southern than in the northern States. The mean temperature is from (12° to 70° P., and does not vary more than to during the year. Thins extremes of heat and cold are unknown; semitropical products. like those of Southwestern Europe, are abundant and to some extent, also, products both of the tropical and cold regions. Around the city of Oaxaca wheat and sugar cane may lie seen growing on the same piece of ground.
Above the temperate lands are the tierras friar, or cold hinds, 7000 feet or more above sea level, with a mean temperature of from 50° to 03° F.
Most of the ventral plateau. with its girdle of mountains. is included in this region, but in great depressions of the surface a warmer temperature and tropical products are found. The less ele vated parts of this region produce cereals and apples, while the higher grounds, some of which extend above the SHOW line. have a sparse vegetation. The lower cold lands arc the most thickly inhabited regions in Owing to the differences of temperature and the effect of the mountain ranges upon the direction of till. winds. the rainfall is very unequally dis tributed. Dinring the rainy season, from the middle of -flay to October. many torrential storms occur iu the southern half of the IZepublie. Lit tle or inn rain falls in the winter or dry season. The cold lands receive only abort one-fifth as much rain as the temperate lands except in some of the mountain districts, where the preeipitation is heavy. The City of has a mean fall of 30 inches a year, which is somewhat in excess of the general supply of the plateau to the north of it. though the precipitation on the moun tain coast lands is two to four Hines as great. The extreme northern part of the plateau is semi arid, reproducing the conditions that prevail in Arizona and New Mexico. The country lies in the zone of trade winds blowing from northeast to southwest, but, as mentioned above, the trend of the ranges modifies their normal direction. Both the Gulf and Pacific coasts are exposed to violent gales, which often do great damage to shipping.