The answer to this question is not actually as simple as you might think. There is not a standard definition that is agreed upon by scientists, nor a standard name! Even though there is no clear consensus for the definition, tropical dry forests are generally considered to be dominated by deciduous vegetation and experience highly seasonal rainfall. The debate mainly centers around the percentage of vegetation that must be deciduous, the number of months without rainfall, and the amount of vegetation that must be woody plants. Neither the definition or the name of tropical dry forests is standardized, probably because they often grade into a different vegetation type.

One consequence of this lack of a standard definition, however, is that it complicates the program of accurately assessing the health and conservation status of tropical dry forests around the world. Regardless of the exact definition used, however, tropical dry forests around the world are in trouble.