According to Genesis, the floodwaters prevailed on the earth for 150 days after Noah entered the Ark.
Genesis 7:24 states that the waters prevailed upon the earth for 150 days. This period follows the rising of the waters and is distinct from the 40 days and 40 nights during which rain fell. The narrative then describes God remembering Noah and causing a wind to pass over the earth, beginning the retreat of the waters.
The 150-day figure is one of several chronological details in the biblical account. Genesis also dates the beginning of the flood, the grounding of the ark, and Noah’s eventual departure. Because the text uses both month and day references, readers have long examined how its chronology fits together.
This number is often confused with the rainfall period. The rain lasts 40 days and nights, while the waters remain dominant for 150 days. Neither number represents the entire time Noah and the animals remained inside the ark.