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The short answer is that we cannot be certain one way or the other.
On day 2 the water vapour was formed in the upper atmosphere (or sky).
Genesis 1:6... God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. 7 And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. 8 And God called the firmament Heaven. And the evening and the morning were the second day.
In Genesis 2 we are told that rain did not fall at the beginning but that the ground was watered by a mist.
Genesis 2:5... for the LORD God had not caused it to rain upon the earth... 6 But there went up a mist from the earth, and watered the whole face of the ground.
On the other hand we are told that a river watered the garden and went out of Eden to split into four rivers. The question we are unable to answer is whether the precipitation described would be sufficient to supply enough water. We have no idea of the land contours or catchment area involved. We might suppose that the river came from underground and was supplemented by streams as it continued its course. The rivers may have been slow flowing if the earth was reasonably flat, but it all becomes speculation.
Genesis 2:10... a river went out of Eden to water the garden; and from thence it was parted, and became into four heads. 11 The name of the first is Pison: that is it which compasseth the whole land of Havilah, where there is gold; 12 And the gold of that land is good: there is bdellium and the onyx stone. 13 And the name of the second river is Gihon: the same is it that compasseth the whole land of Ethiopia. 14 And the name of the third river is Hiddekel: that is it which goeth toward the east of Assyria. And the fourth river is Euphrates.
Rain is next mentioned in Genesis 7 some 1656 years after creation.
Genesis 7:4 For yet seven days, and I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth... 11In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. 12 And the rain was upon the earth forty days and forty nights.
Genesis 8:2 The fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained;
Genesis 8:13 And it came to pass in the six hundredth and first year (of Noah’s life), in the first month, the first day of the month, the waters were dried up from off the earth:
In Genesis 9, God gives Noah the sign of the rainbow as permanent reminder that he would not again completely flood the earth.
Genesis 9:12 And God said, This is the token of the covenant which I make between me and you and every living creature that is with you, for perpetual generations: 13 I do set my bow in the cloud, and it shall be for a token of a covenant between me and the earth. 14 And it shall come to pass, when I bring a cloud over the earth, that the bow shall be seen in the cloud: 15 And I will remember my covenant, which is between me and you and every living creature of all flesh; and the waters shall no more become a flood to destroy all flesh. 16 And the bow shall be in the cloud; and I will look upon it, that I may remember the everlasting covenant between God and every living creature of all flesh that is upon the earth.
We cannot be sure that this was the first time a rainbow was seen but from this time onwards it becomes the sign of the covenant.
Solomon describes the water cycle as it exists today and the different forms of precipitation, mist, fog, rain, sleet, hail and snow are all common though not universal.
Ecclesiastes 1:7 All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again.
We will not know the answer until Christ returns.
I hope you have found this helpful.
May God bless you,