In Noah’s Genesis story, the floodwaters prevailed for 150 days.
Genesis 7:24 states that the waters prevailed upon the earth for 150 days. This is a different measurement from the 40 days and 40 nights of rain described earlier in Genesis 7:12. The rainfall stopped, but the floodwaters continued to dominate the landscape before beginning to recede.
Genesis 8 then follows the retreat of the water in stages. The ark comes to rest on the mountains of Ararat, the mountain tops become visible later, and Noah eventually leaves the ark after receiving God’s instruction. These sequential details explain why the complete flood episode lasted longer than the rainfall itself.
Readers sometimes merge the two numbers and answer 40 days for every flood duration. That is not what the text says: 40 days describes rain, while 150 days describes the period during which the waters prevailed. Keeping those stages separate resolves the most common numerical confusion in the narrative.