In Genesis, how long did rain fall during the flood at the start of Noah’s story?

Genesis 7:12 says rain fell upon the earth for forty days and forty nights. This is the duration of the initial rainstorm in the flood narrative. Genesis also describes the waters prevailing for a longer period, so the forty-day figure should not be mistaken for the entire time Noah remained aboard the Ark.

The story gives several time markers: Noah enters the Ark, rain begins, the waters rise, and later the Ark comes to rest. Genesis 7:24 says the waters prevailed for 150 days, while Genesis 8 describes the gradual drying process. These separate numbers explain why summaries that call the whole flood “forty days” simplify the chronology.

The number forty also appears in other biblical narratives, including Moses’ time on Sinai and Israel’s wilderness period. In the Ark account, however, the explicit phrase refers to continuous rain at the flood’s beginning.