AGRICULTURAL SURVEY OF SOUTH AMERICA 77 
can be seen everywhere. Yerba mate is one of the few trees which 
the ants do not attack. It is said that the voracious locusts that 
constitute a national calamity in Argentina are not a serious pest in 
Paraguay. 
GENERAL FEATURES OF THE CLIMATE 
The upper fourth of Paraguay is in the Tropics and the lower 
three-fourths in the Temperate Zone. The climate is described as 
hot in summer but not unhealthful, being tempered by the mountains, 
rivers, and winds. It is subject to sudden changes in temperature 
depending on change in the direction of prevailing winds. When 
the wind blows steadily from the north for several days, the tempera- 
ture is high and the atmosphere becomes saturated with moisture. 
When the u pamperos" (winds cooled by the icebergs south of Cape 
Horn) of the Argentine sweep up from the south there is a sudden 
fall in temperature, often accompanied by heavy rain. In winter 
(June to September) the temperature often remains but little above 
freezing for several days, and other days are hot like midsummer. 
The winters are mild, and orange trees, bougainvillea, roses, dahlias, 
poinsettias, nasturtiums, and other flowers continue in full bloom. 
As Paraguay is south of the Equator, the seasons are just the reverse 
of those in the Northern Hemisphere. 
In the annual report for 1923 of the National Agricultural Bank, 
various sources of information regarding the climate of Paraguay 
are mentioned. Among them are included observations made at 
the meteorological stations of Paraguay, the data collected and pub- 
lished by the Meteorological Bureau of Argentiua in the adjoining 
frontier regions, the series of continuous observations and studies 
extending through a period of 40 years since 1884, particularly with 
reference to agriculture, made by Moises S. Bertoni 18 in Alta Parana, 
the correlative series for a period of 10 years in the extinct national 
school of agriculture, now the Jar din Botanico, and the succeeding 
series carried on by the director of the botanical garden. 
At present, four stations exist for taking meteorological observa- 
tions, at Asuncion, Jardin Botanico (near Asuncion), Puerto Bertoni, 
and Ypacarai. Rainfall observations are taken at 19 stations. The 
revolution of 1923 seriously interfered with the series of observations 
for that year, which are therefore incomplete. 
Temperatuke 19 
The mean temperature of Paraguay is said to be about 81° F. in 
summer and 63° F. in winter. The year 1923 is fairly typical. For 
that year the classification of temperatures by months is given in 
Table 52. The hot season lasts from October to March and the cold 
season from April to September. 
18 Bertoni, M. S. Estudio de las periodicidades diarias aparentes o reales de las lluvias y tempestades 
. . . Alto Parana, Puerto Bertoni, Imprenta y edition "Ex Sylvis," 1918. (Description fisica y eco- 
nomica del Paraguay. Div. 2, Meteorologia y climatologia. Section 24, Prognosia del tiempo, Num 
24:2). 
Bertoni, M. S. Memoria sobre la existencia de lluvias periodicas en determinados dias del afio un factor 
mas para la prevision del tiempo . . . Alto Parana Puerto Bertoni. Imprenta y edicion "Ex Sylvis,' 
1918. 
19 Banco agricola del Paraguay, Asuncion. Memoria . . . correspondiente al ano 1923 . . . Asuncion. 
La Colmena S. A., 1924. 
