central valley
location
This region is located in the country’s center and is bordered to the north by the Central Volcanic Range, the Cerros de Escazú, Tablazo, Cedral and the Candelaria Ridge to the south, the Monte del Aguacate to the west and the Cordillera de Talamanca to the east. It includes the country’s largest urban centers: San José, Heredia, Alajuela and Cartago.
ecology
According to the Holdridge life zone classification, it contains areas ranging from wet tropical forest to rainy premontane forests. Some areas contain wet tropical forests with average temperatures of 22°C (72°F) and annual precipitation of 2,300 mm on average.
climate
This region is part of the Volcanic Structural Region and the Tilarán Band, which holds valleys that are influenced by the conditions of the Pacific and the Caribbean.
Western Central Valley: Its lower regions (Atenas, Turrúcares, La Garita and La Guácima) have a dry climate with a marked influence from the Pacific. Its intermediate regions (San José, Heredia, Cartago) experience a temperate climate, while the higher regions are rainy and cold, typical of the mountainous area. It has around 148 rainy days.
Eastern Valley: This includes the valleys of El Guarco and Orosi, with weaker rain that comes over the mountain passes and is mostly influenced by the Caribbean weather system. It has around 163 rainy days, mostly in the months of December, January and February. However, the Western Valley has higher total precipitation (2,300 mm) than the Eastern Valley (1,700 mm).
In general, the Central Region has a dry season that lasts between December and March and a rainy period between May and October. A very popular veranillo occurs at the end of June, known as the “Veranillo de San Juan”. Temperature varies with altitude, with lower temperatures at higher locations. The Western Valley has an average altitude of 1,100 masl, while the Eastern Valley is higher, at 1,300 masl. The highest temperatures are observed in March and April in the former, and in April and May in the latter.