This question comes up often in relation to pre-flood geology and, for that matter, everyday life in Pre-delugian times. So, had it ever rained before the Flood? Or was the only precipitation a mist that God caused to rise up from the ground?
Genesis 2:4-6 These are the generations of the heavens and of the earth when they were created, in the day that the LORD God made the earth and the heavens, And every plant of the field before it was in the earth, and every herb of the field before it grew: for the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground. But there went up a mist from the earth, and watered the whole face of the ground.
From that we know that, when God made plants, grass, trees, etc, (Day 3 of Creation) He made a mist to come up out of the ground to water the ground, and the plants God had just made. But how long did it do this? Did it continue to rise every morning for the 1656 years until the flood of Noah? And had it never rained anywhere on Earth until that happened?
Genesis 2:7-10 And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul. And the LORD God planted a garden eastward in Eden; and there he put the man whom he had formed. And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil. And a river went out of Eden to water the garden; and from thence it was parted, and became into four heads.
Notice that the purpose of this river was to water the Garden. But that was the stated purpose of the Mist! Furthermore, a mist rising from the ground generally is absorbed quickly by the plants and, as soon as the day grows warmer, it evaporates. Anyone in a fog-inclined locale knows this. So for a “great river” to be created, unbelievably enormous amounts of mist would have to be precipitated.
Furthermore, short of miraculous intervention, God couldn’t have kept the Earth from being rained on all those years. As long as there were seas, sunshine, and temperatures warm enough to permit life on earth, there will be evaporation from the bodies of water into the atmosphere. This moisture will then rise into the cooler layers of the upper atmosphere and condense into clouds. When enough moisture condenses it will no longer be able to stay in suspension and it will fall. This is called rain, and is an unavoidable fact of science.
So if this phenomenon was so unavoidable, why did God have to specifically cause a mist to rise from the ground on the Third Day? Well, you see, those three conditions I outlined above had not yet been met on the Third Day! God had formed seas, and planted grass, trees, and all sorts of plants which means that the temperature must have been temperate… but God didn’t “create” the sun until the fourth day!
Genesis 1:16-19 And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good. And the evening and the morning were the fourth day.
Since the sun hadn’t shone upon the Earth until the fourth day, the evaporation cycle would not have worked nearly as well, although any temperature above freezing will cause at least some evaporation. Hence, if God wanted his newly made plants watered, He had to do it Himself. But how?
Remember, God had just that same third day separated the land from the sea. This means that He lifted the land mass up out of the sea. What happens when you lift a pile of sand out of water? Why, it remains rather damp for some time. What happens to damp sand left to itself in temperate (say 90 degree) weather? Even without sunlight, it evaporates. And evaporated water from land is called… mist.
For an easy example of this, wait for a summer day when it rains and the temperature remains high, while the sun remains hidden by clouds. You will literally see mist rising from the ground. This is the basic phenomenon that God used to water His newly created plants before the Sun was there to help.
But once God had created – or revealed – the Sun to Earth, the evaporation cycle would begin in earnest and begin causing rain which naturally creates rivers. The conclusion of all of this is that God did not cause a mist and prevent rain for 1656 years before the flood, but only in that one isolated incident on day three of Creation week.