Clouds are called:

A. Clouds of Heaven

Dan 7:13 I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought Him near before Him.

B. Windows (or Floodgates) of Heaven

Gen 7:11 In 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.

Dan 7:13 I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him.

C. Clouds of Wisdom

Job 38:37 Who can number the clouds in wisdom? Or who can stay the bottles of heaven,

D. Chambers of God

Psalm 104:3 Who layeth the beams of His chambers in the waters: who maketh the clouds His chariot: who walketh upon the wings of the wind:

Psalm 104:13 He watereth the hills from His chambers: the earth is satisfied with the fruit of Thy works.

E. Chariot of God

Psalm 104:3 Who layeth the beams of his chambers in the waters: who maketh the clouds his chariot: who walketh upon the wings of the wind:

F. Holder of rainbow

Gen 9:13-14 I do set My bow in the cloud, and it shall be for a token of a covenant between Me and the earth. And it shall come to pass, when I bring a cloud over the earth, that the bow shall be seen in the cloud:

Clouds Have been used for many purposes:

A. To lead Israel through wilderness

Exod. 13:20-21 And they took their journey from Succoth, and encamped in Etham, in the edge of the wilderness. And the LORD went before them by day in a pillar of a cloud, to lead them the way; and by night in a pillar of fire, to give them light; to go by day and night:

B. God came down in & spoke from clouds

Psalm 99:7 He spake unto them in the cloudy pillar: they kept His testimonies, and the ordinance that He gave them.

Exod 19:9 And the LORD said unto Moses, Lo, I come unto thee in a thick cloud, that the people may hear when I speak with thee, and believe thee for ever. And Moses told the words of the people unto the LORD.

Exod 34:5 And the LORD descended in the cloud, and stood with him there, and proclaimed the name of the LORD.

Num 11:25 And the LORD came down in a cloud, and spake unto him, and took of the Spirit that was upon him, and gave it unto the seventy elders: and it came to pass, that, when the Spirit rested upon them, they prophesied, and did not cease.

C. Show the Glory of God

Exod 16:10 And it came to pass, as Aaron spake unto the whole congregation of the children of Israel, that they looked toward the wilderness, and, behold, the glory of the LORD appeared in the cloud.

D. At giving of law

Exod 19:9 And the LORD said unto Moses, Lo, I come unto thee in a thick cloud, that the people may hear when I speak with thee, and believe thee for ever. And Moses told the words of the people unto the LORD.

Exod 9:16 And in very deed for this cause have I raised thee up, for to shew in thee My power; and that My name may be declared throughout all the earth.

Exod 24:16 And the glory of the LORD abode upon mount Sinai, and the cloud covered it six days: and the seventh day He called unto Moses out of the midst of the cloud.

In the New Testament:

A. When Christ was baptized

Matt 3:16 And Jesus, when He was baptized, went up straightway out of the water: and, lo, the heavens were opened unto Him, and He saw the Spirit of God descending like a dove, and lighting upon Him:

Mark 1:10 And straightway coming up out of the water, He saw the heavens opened, and the Spirit like a dove descending upon him:

Luke 3:22 And the Holy Ghost descended in a bodily shape like a dove upon Him, and a voice came from heaven, which said, Thou art my beloved Son; in Thee I am well pleased.

John 1:32 And John bare record, saying, I saw the Spirit descending from heaven like a dove, and it abode upon him.

B. At transfiguration of Christ

Matt. 17:5 While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is My beloved Son, in whom I am well pleased; hear ye Him.

C. After Christ died for our sins, & rose from the dead He ascended to heaven in a cloud

Acts 1:9 And when He had spoken these things, while they beheld, He was taken up; and a cloud received Him out of their sight.

D. Christ will come again in a cloud

Luke 21:27 And then shall they see the Son of man coming in a cloud with power and great glory.

Acts 1:11 Which also said, Ye men of Galilee, why stand ye gazing up into heaven? This same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen Him go into heaven.

E. There is a great cloud of witnesses

Heb 12:1 Wherefore seeing we also are compassed about with so great a cloud of witnesses, let us lay aside every weight, and the sin which doth so easily beset us, and let us run with patience the race that is set before us,

The heavens declare the glory of God

Psalm 19:1 The heavens declare the glory of God; and the firmament sheweth his handywork.