For how many days and nights does Genesis say rain fell during the Flood?

Genesis says rain fell on the earth for 40 days and 40 nights during Noah’s Flood.

Genesis 7:12 uses that exact duration when describing the rain. The number 40 has a recurring narrative role in the Bible, appearing in other stories involving testing, travel, or preparation, but the Flood account also gives additional time spans that should not be merged with it.

For example, Genesis says the waters prevailed for 150 days, a longer period covering the persistence of the Flood waters rather than only the rainfall. This is why 40 days and 150 days are both associated with the story but answer different questions. The familiar phrase refers specifically to the rain.