The striking variety in temperature and precipitation results principally from differences in elevation. Temperatures range from very hot at sea level to relatively cold at higher elevations but vary little with the season. At Bogotá, for example, the average annual temperature is 15°C, and the difference between the average of the coldest and the warmest months is less than 1°C. More significant, however, is the daily variation in temperature, from 5°C at night to 17°C during the day.

Colombians customarily describe their country in terms of the climatic zones: the area under 900 meters in elevation is called the hot zone (tierra caliente), elevations between 900 and 1,980 meters are the temperate zone (tierra templada), and elevations from 1,980 meters to about 3,500 meters constitute the cold zone (tierra fría). The upper limit of the cold zone marks the tree line and the approximate limit of human habitation. The treeless regions adjacent to the cold zone and extending to approximately 4,500 meters are high, bleak areas (usually referred to as the páramos), above which begins the area of permanent snow (nevado).

About 86 percent of the country's total area lies in the hot zone. Included in the hot zone and interrupting the temperate area of the Andean highlands are the long and narrow extension of the Magdalena Valley and a small extension in the Cauca Valley. Temperatures, depending on elevation, vary between 24°C and 38°C, and there are alternating dry and wet seasons corresponding to summer and winter, respectively. Breezes on the Caribbean coast, however, reduce both heat and precipitation.

Rainfall in the hot zone is heaviest in the Pacific lowlands and in parts of eastern Colombia, where rain is almost a daily occurrence and rain forests predominate. Precipitation exceeds 760 centimeters annually in most of the Pacific lowlands, making this one of the wettest regions in the world; in eastern Colombia, it decreases from 635 centimeters in portions of the Andean piedmont to 254 centimeters eastward. Extensive areas of the Caribbean interior are permanently flooded, more because of poor drainage than because of the moderately heavy precipitation during the rainy season from May through October.

The temperate zone covers about 8 percent of the country. This zone includes the lower slopes of the Cordillera Oriental and the Cordillera Central and most of the intermontane valleys. The important cities of Medellín (1,487 meters) and Cali (1,030 meters) are located in this zone, where rainfall is moderate and the mean annual temperature varies between 19°C and 24°C, depending on the elevation. In the higher elevations of this zone, farmers benefit from two wet and two dry seasons each year; January through March and July through September are the dry seasons.

The cold or cool zone constitutes about 6 percent of the total area, including some of the most densely populated plateaus and terraces of the Colombian Andes; this zone supports about onefourth of the country's total population. The mean temperature ranges between 10°C and 19°C, and the wet seasons occur in April and May and from September to December, as in the high elevations of the temperate zone.

Precipitation is moderate to heavy in most parts of the country; the heavier rainfall occurs in the low-lying hot zone. Considerable variations occur because of local conditions that affect wind currents, however, and areas on the leeward side of the Guajira Peninsula receive generally light rainfall; the annual rainfall of thirty-five centimeters recorded at the Uribia station there is the lowest in Colombia. Considerable year-to-year variations have been recorded, and Colombia sometimes experiences droughts.

Colombia's geographic and climatic variations have combined to produce relatively well-defined "ethnocultural" groups among different regions of the country: the Costeño from the Caribbean coast; the Caucano in the Cauca region and the Pacific coast; the Antioqueño in Antioquia, Caldas, Risaralda, and Valle del Cauca departments; the Tolimense in Tolima and Huila departments; the Cundiboyacense in the interior departments of Cundinamarca and Boyacá in the Cordillera Oriental; the Santandereano in Norte de Santander and Santander departments; and the Llanero in the eastern plains. Each group had distinctive characteristics, accents, customs, social patterns, and forms of cultural adaptation to climate and topography that differentiates it from other groups. Even with rapid urbanization and modernization, regionalism and regional identification continued to be important reference points, although they were somewhat less prominent in the 1980s than in the nineteenth and early twentieth centuries.

Data as of 1988