The climate is mild and relatively dry. Average annual rainfall is 1395 mm mostly between May and October. The maximum average temperature is 25.6deg. C. Temperature may drop as low as 15deg. C some nights in December or rise to 38deg.on an April or May afternoon.
Soils are mostly alluvial, with some granite and basalt outcrops.
A series of short rivers drain the immediate hinterland of the province, separating the coastal slope from the Dong Nai Basin to the North. According to Nguyen Bich Thao, the Reserve has 43 km of rivers, of which 10 km have year round water. About a third of the Reserve is very fragile wetland, a home for a variety of wildlife from molluscs and crustaceans to mammals and to roosting sites for migratory and endemic birds. Vietnam's wetlands form the wintering or staging places for some 100 migratory birds - hence they are a resource of international importance. Thao found 13 frog and salamander species.