A general judgment on the Brazilian climate is made complex and difficult by the vastness of the territory, which belongs to three different climatic zones and has a great variety of altimetric conditions, so that the distribution of meteorological data according to latitude is altered. It should be added that only a few stations can offer us thermal, baric, udometric elements for a period of thirty years, and that they are mostly coastal and sub-coastal, while for vast inland regions we have only sporadic and occasional elements, due to some travelers or recent installations. of observers. Only when the observations are numerous and regular will it be possible, with sufficient approximation, to establish what are the salient characteristics of the Amazonian climate, the climate of the plateau, and the mountain climate,
Likewise, while we can say that we know, together with what refers to sub-coastal sea currents and tidal currents, the wind regime of the various port areas, and we are able to fix, with sufficient approximation, in the same valley of the Solimões, the limit of the geral wind, the scarcity of our knowledge on the baric conditions of a large part of the interior does not grant sure conclusions on the formation of cyclonic and anticyclonic areas and, in general, on the wind regime, on which the agricultural and livestock industry.
With regard to the Amazon climate, it must be remembered that, in addition to the theoretical dissent on the influence exerted on hygienic conditions, there is a great diversity in the results of the observations and in the judgments of scholars and travelers: certainly this discord is largely due to the great variety of conditions in the individual zones, conditions that favor or hinder the acclimatization of the immigrant European. It will therefore be necessary to expand and multiply the studies in this sense too so that the effective hygienic conditions of many areas of Brazil can be established: for now, the meditated conclusion of a geologist deserves to be referred to, to whom fundamental related works are due. to the Brazilian area: ” In some parts of Brazil the climate is as good as in any part of the world: such are the highlands of Minas Geraes, Goyaz and the Southern States, São Paulo, Paraná, Santa Catharina, Rio Grande do Sul. The elevated and arid regions of the interior are pleasant and healthy, but the marshy areas of the Amazonas, Pará, and Matto Grosso must always be avoided when one is not immunized from intestinal disturbances and malignant fevers “(JC Branner, 1919).
According to the most recent scholars, it seems appropriate to divide all of Brazil into three zones based on the average annual temperature: A, an equatorial climate zone with an average annual temperature above 25 ° (tropical zone); B, of subequatorial climate with average annual temperature between 20 ° and 25 ° (subtropical zone); C, with a temperate climate (temperate zone) with an average temperature between 10 ° and 20 °. Each of these areas must be divided into sections according to the annual rainfall trend, so that the following classification of Morize can be adopted, also accepted by the Eredia:
A1. Very humid equatorial climate have the coast of Maranhão and Piauhy as well as a large part of the Amazon valley: the temperature is warm, but not torrid, and constant with very few variations throughout the year; it is very humid, and therefore debilitating and unnerving, but not excessively unhealthy. In Belem the average of the coldest month is 25 °, 1, that of the hottest month 26 °, 5; in Manáos, the coldest month averages 26 °, 7, the hottest month 28 °, 3; In Porto Velho the coldest month has an average of 27 ° and the warmest month of 29 °, 3. Variations between absolute extreme temperatures are also quite slight. The rainfall that is abundant and goes from a minimum of mm. 1312 to a maximum of mm. 3137, is not evenly distributed throughout the year, but a rainy season and a dry period are noted. At the coast, the dry season lasts from 4 to 5 months and generally extends from July to November, but it decreases as the course of the river rises both in duration and in intensity. The time of the maximum rains always falls between March and April and for all localities; in the more inland areas, the rainy period begins in October and lasts until May. Overall it can be said: in the Amazon it rains a lot, the rain falls in a large number of days distributed throughout the year, and south of the equator the rainy period corresponds to the austral summer and autumn. The dominant wind along the Amazon is the trade wind that blows from the NE. up beyond Manáos and then in an east-west direction. In the’ high Amazons and especially in the basin of the southern tributaries the action of the trade wind is opposed by a S. or SW wind. coming from the Cordillera, which causes the temperature to drop considerably, producing in the period from May to August (southern winter) the phenomenon known locally ascold. For Brazil travel information, please check zipcodesexplorer.com.
A 2. In the localities of the interior, both north and south of the Amazon River, and precisely in the states of Amazonas and Pará as well as in the southern part of Maranhāo, in Goyaz and in Mato Grosso, the type of equatorial climate has been observed referred to as humid-continental in our table. The temperature due to the greater distance from the coast, undergoes more notable variations during the year: thus in Maranhão, in Barra da Corda, on the Rio Mearim, the absolute extreme temperatures vary between 39 °, 4 and 12 ° while near the coast, in S. Bento, these extremes become 36 °, 4 and 18 °, 5; so in the Matto Grosso at S. Luiz de Cáceres extreme temperatures of 40 °, 8 and 3 °, 8 were observed and in Corumbá 40 °, 6 and 0 °, 8.
The average monthly temperature undergoes much minor variations (from 3 to 4 degrees) and has a maximum in the months of November and December and a minimum in the months of June and July, following the declination of the sun and independently or almost independently of the rainfall.
In these regions, although the amount of annual rainfall is sometimes less than that recorded by the coastal stations, the rain is well distributed throughout the year and the drought is unknown to them. In the annual distribution of rain, however, there is a maximum in January and February and sometimes in March and a minimum in the months of June and July. Relative humidity as well as nebulosity show a trend similar to that of rainfall.
A 3. In the vast north-eastern region of Brazil which, starting from the southern area of Piauhy, extends into the states of Ceará, Rio Grande do Norte, Parahyba and the interior of Pernambuco and Bahia up to the northern section of Minas Geraes, the annual amount of rainfall and their distribution determines the third type of equatorial climate called semi-arid. The average temperature in the various months of the year is always high, so that the difference between the average of the coldest month, June or July, and the average of the hottest month, December, does not exceed 1 or 2 degrees.