Why are Central American highlands cooler than coastal lowlands?

Central American highlands are cooler than coastal lowlands primarily due to the effect of elevation on temperature. While the region’s climate is essentially tropical, elevation serves to mitigate the heat typically associated with tropical latitudes.1

As altitude increases, temperatures decrease. In the wet tropics, for example, temperatures generally fall by approximately 0.5 °C (0.9 °F) for every 100 meters (328 feet) of elevation gained. This phenomenon, known as the lapse rate, results in distinct vertical temperature zones. Consequently, while coastal areas remain consistently hot, the highlands experience significantly lower average temperatures, creating more temperate or even cold conditions depending on the specific altitude.2341