TROPICAL CLIMATE 3 



ing a daily range of only about ii°. At this city the night 

 temperature is about 75° and the day temperature about 86°. 

 In Honolulu, the lowest temperature recorded in 30 years is 

 52" and the highest 89° F., giving a total range of 37° F. 



With the very slight range of temperature in tropical coun- 

 tries, it is obvious that no sudden changes of temperature can 

 possibly occur. There is, therefore, ordinarily no occasion for 

 any changes in the nature or weight of clothing from one sea- 

 son to another. So far as the extremes of temperature and 

 the range of temperature and consequent necessary adjust- 

 ments of the body are concerned, the Tropics j)ossess a decided 

 advantage over all temperate and less favored climates. 



The crops which are characteristic of the Tropics extend 

 for considerable distances outside of the strict boundaries of 

 the tropical zone. It is necessary, therefore, in a discussion of 

 tropical agriculture to include subtropical countries in order 

 not to be forced to draw too arbitrary boundaries. In the mat- 

 ter of tropical climate an important factor in further soften- 

 ing and ameliorating the tropical heat is found in the trade 

 winds. These winds rise about 30° north and south of the 

 Equator and blow toward the Equator with a slight westerly 

 deflection as far as the doldrum belt. North of the Equator, 

 therefore, the trade wind is a northeast wind, while south of 

 the Equator it is a southeast wind. The "trades" are uni- 

 versally gentle winds and in most of the countries within the 

 trade-wind belt, especially in islands, the trade winds blow 

 practically continuously night and day for from 250 to 280 

 days of the year. These gentle winds are dry and cooling. 

 When the velocity of the trade wind is relatively high the evap- 

 oration caused by the "trades" is very great. They therefore 

 not only serve to cool the body, but also to lower the tempera- 

 ture of plants by transpiration. 



At irregular intervals the trade winds are interrupted by 

 winds variously known as reverse trades, monsoons, kona 

 winds, etc. The southeast trades become southwest monsoons 



