[2] Their southern and western limits, however, are not precisely fixed, as these are restricted by 'subtle environmental changes or transitions from one zone [the Highlands] to another [the Lowlands],' rather than conspicuous geographic features.

[3][note 4] The Lowlands fully encompass Belize, the Guatemalan department of Peten, and the Mexican states of Campeche, Yucatán, and Quintana Roo.

[6][7][8][note 6] As with the Lowlands–Highlands border, the boundaries of the Lowlands' internal subdivisions are not precisely fixed, being rather formed by gradual environmental or climatic transitions.

[6][note 7] The Northern Lowlands are generally characterised by relatively low rainfall and high temperatures, typically ranging within 20–80 inches (510–2,030 mm) per annum and 77–95 °F (25–35 °C), respectively.

[11][note 8] The Central Lowlands are generally characterised by relatively low rainfall and high temperatures, typically ranging about 80 inches (2,000 mm) per annum and 77–95 °F (25–35 °C), respectively.

[12] Their terrain is predominated by low east–west ridges of folded and faulted limestone, covered by tropical forests, grasslands, and wetlands.

[15][note 9] The Southern Lowlands are generally characterised by relatively high rainfall and temperatures, typically ranging within 80–120 inches (2,000–3,000 mm) per annum and 77–95 °F (25–35 °C), respectively.

[19] The Southern Lowlands generally encompass portions of Chiapas, Tabasco, and Campeche in Mexico, Huehuetenango, El Quiche, Alta Verapaz, Izabal, and Peten in Guatemala, Cayo, Stann Creek, and Toledo in Belize, and Cortes, Santa Barbara, and Copan in Honduras.

'[30] These have revealed, for instance, particularly severe or prolonged droughts during AD 200–300, 420, 820–870, 930, and 1020–1100, some of which are thought to have played a part in the collapse of various ancient cities.