Why are they generally in the tropics? The tropics get lots of sun and so are always warm, unless you're at an elevation of something over 5,000 feet, such as in the Andes or East African highlands. The average difference in temperature in Belem, near the mouth of the Amazon in Brazil, for example, is about 3. F between January and July. In contrast, the average July temperature in New York is about 35F warmer than in January. Why? It's all about the movement of air. Onito Lima 72 TROPIC OF CAPRICORN Bogot 57 Sanliagol 66 Punta Arenas 48 Caracasa Manaus 79 Porto Velho 77 La Par 52 Buenos Aires 75% Average January Temperature Cayenne 181* Brasilla 70 Asuncin 83 Belem 77 FAHRENHEIT Over 86 68 to 86 50 to 68 -32 to 50 Under 32 EQUATOR Recife 181 Rio de Janeiro -79 CELSIUS Over 30 20 to 30 10 to 20 0 to 10 Under 0 Quito Lima 59 Bogot 56 .. OF CAPRICORN Santiago 46 Manaus 81 Punta Arenas 35 Porto Velho 75 La Paz 45 Buenos Aires 48* Average July Tempe