Guanacaste has a normally hot and dry climate, that is why it is the favorite beach destination in Costa Rica. The traditional Guanacaste climate is hot, dry, dry winds, brown and grey landscapes, tropical dry forest and in general a stable climate all year round, except for October and November, when it rains a lot.  The annual average temperature ranges between 26 Guanacaste and 33 ° C at the bottom, and between 9 and 11 ° C at the top, being the Arenal area of ​​the cooler and wettest area.

The annual rainfall in Guanacaste is between 1,500 and 2,000 mm. It is a province rich in biodiversity due to these climatic conditions, with amazing landscapes for lowland plains, forests, mountains, volcanoes and beaches.  Of the Cordilleras de Guanacaste and Tilarán flow several rivers that form an alluvial plain drained by the Tempisque River, which runs and feeds much of the province before emptying into the Gulf of Nicoya.