The highest temperature reached at 39⁰C - 40.3⁰C (June, July) and the lowest temperature was at 6.7 - 7.3⁰C (December, January). The difference between the hottest and coldest months is around 2.3 - 3.3⁰C.

Floods in Phong Nha - Ke Bang often occur quickly and strongly due to has  narrow, steep relief. For example, in 2006 shows that 6 floods, of which 3 were recorded at alarm level II and III, water levels in the Gianh River were 13,32m above alarm level II at, or 0.32m higher than alarm level III.

The number of erosion and landslides in the Phong Nha Ke Bang region have been dominated by the terrain, season and land use as well. U Bo Mountains, where is located Phong Nha  Ke Bang south, is the highest number of erosion and landslides. Other sites, such as Da Deo, Cong Troi, and Khu Dung are happened  in the rainy season.