1. Located near the equator, it is controlled by the equatorial low pressure belt all year round and has a lot of rainfall.

2. There is a gap on the east side of the Amazon Plain facing the Atlantic Ocean, and the Guiana Plateau in the north, the Brazilian Plateau in the south, and the Andes Mountains in the west, which is conducive to the moist air flow from the Atlantic Ocean to penetrate deep into the inland.

3. The South Equatorial Warm Current increases temperature and humidity.

4. The southeast trade winds and northeast trade winds bring water vapor from the Atlantic Ocean.

5. The west side is lifted by the Andes Mountains, and there is a lot of orographic rainfall.