Climate:
Because the Earth tilts at an angle of 23.5 degrees, at some point in the year the sun is directly over one of these lines - known as the 'solstices'. The 'equinoxes' is when the sun is directly over the equator. Therefore, within the two red lines, solar radiation is the most intense which means that this area of the planet warms the most. This leads to an average temperature of 20 degrees all year round with little seasonal variation, which is preferable for plant growth.
Such warm temperature leads to lots of evaporation, and as the warm, moist air rises, it cools and eventually condenses and falls back to the Earth as rain. As strange as it sounds, the warmest places on the planet also tend to be the wettest. Tropical rainforests can have as much as 300 cm of rain a year. The humidity in tropical rainforests ranges from 77%-88%. Tropical rainforest areas technically don't have any seasons, not even a dry season, it's just wet, all the time. Here rainfall can last for up to three months never stopping!
Such warm temperature leads to lots of evaporation, and as the warm, moist air rises, it cools and eventually condenses and falls back to the Earth as rain. As strange as it sounds, the warmest places on the planet also tend to be the wettest. Tropical rainforests can have as much as 300 cm of rain a year. The humidity in tropical rainforests ranges from 77%-88%. Tropical rainforest areas technically don't have any seasons, not even a dry season, it's just wet, all the time. Here rainfall can last for up to three months never stopping!