The southern edge of the western highlands is marked by the Sierra Madre, which stretches from the Mexican border south and east, and continues at lower elevations toward El Salvador. The mountain chain is characterized by steep volcanic cones, including Tajumulco Volcano (4,220 m/13,845 ft, the highest point in the country and Central America. All of Guatemala’s 37 volcanoes (4 of them active Pacaya, Santiaguito, Fuego and Tacaná), are in this mountain chain, and are frequent in the highlands.
The northern chain of mountains begins near the Mexican border with the Cuchumatanes range, then stretches east through the Chuacús and Chamá sierras, down to the Santa Cruz and Minas sierras, near the Caribbean Sea. The northern and southern mountains are separated by the Motagua valley, where the Motagua river and its tributaries drains from the highlands into the Caribbean being navigable in its lower end, where it forms the boundary with Honduras.
Its climate is hot and humid in the Pacific and Petén Lowlands – more temperate in the highlands, to freezing cold at the high of the Cuchumatanes range, and hot/drier in the easternmost departments.
Guatemala's location on the Caribbean Sea and Pacific Ocean makes it a target for hurricanes, including Hurricane Mitch in 1998 and Hurricane Stan in October 2005, which killed more than 1,500 people.