According to Genesis, how many days and nights did rain fall before the Ark’s flood?

According to Genesis, rain fell for 40 days and 40 nights during the flood associated with Noah’s Ark. Genesis 7:12 gives this duration after Noah and the animals entered the vessel.

The number 40 has a recurring role in biblical narratives, including Moses’ time on Mount Sinai and the Israelites’ years in the wilderness. In the flood account, however, the 40-day period describes the continuing rainfall, not the entire time that the floodwaters covered the earth.

That distinction is important. Genesis also says the waters prevailed for 150 days, so “40 days” and “150 days” refer to different measurements in the story. The rain’s duration is therefore not the same as the total period of rising, prevailing, and receding waters. Popular summaries often compress these separate time spans into one simplified timeline.