Tropical rainforests often have high temperatures year-round due to their proximity to the equator, ranging from 20 - 25°C. A form of seasonal variation is present in tropical climates in the form of the wet and dry seasons, with the wet season lasting from late winter to spring, and the dry season from autumn to early winter. This is shown in the considerable drop in rainfall from July to September in the climograph of a city in Borneo. During the wet season, rainfall is very heavy, precipitating an average of 280mm of rain per month at its peak. The combination of heavy rainfall and high temperatures leads to high humidity in tropical rainforests, with the Amazon having an average humidity of 88% during the wet season and 77% in the dry season according to the WWF.

A common element of tropical rainforests is very large rivers running throughout them, such as the Amazon, Congo, and Mekong. These rivers exist due to the heavy rainfall that rainforests experience. Heavy rainfall also leads to the issue of flooding in lowland tropical rainforests, such as in Bangladesh and in Northeastern Brazil, both prone to flooding due to their low elevations. This image was provided by Pixnio.