In Genesis, the Flood waters prevailed over the earth for 150 days.
Genesis 7:24 states that the waters prevailed upon the earth for 150 days. Genesis 8 then describes the waters gradually receding, with the Ark coming to rest and the landscape slowly becoming visible. The 150-day figure is therefore part of the account’s chronology after the waters have risen.
This number is commonly confused with the 40 days and 40 nights of rain mentioned earlier in the story. The two figures refer to different parts of the narrative: 40 days and nights describe the rain, while 150 days describe the period during which the waters prevailed.
Genesis also uses month and day references to mark the recession of the waters. Because the passage contains several chronological statements, translations and interpretations sometimes discuss how the intervals fit together, but the explicit “150 days” statement remains clear.