In Noah’s Ark, how many days and nights does Genesis say rain fell?

Genesis says rain fell for forty days and forty nights in the story of Noah’s Ark.

Genesis 7:12 uses this repeated biblical time formula when describing the rainfall after Noah, his family, and the animals entered the Ark. The same chapter distinguishes this period of rainfall from the longer period during which the floodwaters remained on the earth.

Because the expression is so memorable, people sometimes use “forty days and forty nights” as if it described the entire Flood. In Genesis, however, the waters rise and later recede over a much longer narrative chronology. The text says the waters prevailed for 150 days before the account moves toward the Ark’s resting and the eventual drying of the ground.

The number forty also appears frequently elsewhere in the Bible in periods of testing, travel, or preparation. In this passage, it is specifically the duration of the rain, not a measurement of the Ark’s size or the total length of the catastrophe.