Quran 24:43:

وَيُنَزِّلُ مِنَ ٱلسَّمَآءِ مِن جِبَالٍ فِيهَا مِنۢ بَرَدٍ فَيُصِيبُ بِهِۦ مَن يَشَآءُ وَيَصْرِفُهُۥ عَن مَّن يَشَآءُ

He sends down (hails) from the sky, from mountains in it of ice, and strikes there with whom He wills, and averts it from whom He wills.

Ibn Kathir writes under commentary of this verse 24:43 (link):

... وَيُنَزِّلُ مِنَ السَّمَاء مِن جِبَالٍ فِيهَا مِن بَرَدٍ ...

(and He sends down from (Min) the sky, from (Min) mountains in it of (Min) ice,)

Some of the grammarians said that the first Min describes the place from which it is coming, the second specifies from which part of the sky it comes, and the third means some kind of mountains. This is based on the view of those scholars of Tafsir who say that, مِن جِبَالٍ فِيهَا مِن بَرَدٍ from (Min) mountains in it of (Min) ice, means that there are mountains of hail in the sky from which Allah sends down ice.

Imam Qurtabi wrote under the commentary of this verse (link):

{ وَيُنَزِّلُ مِنَ ٱلسَّمَآءِ مِن جِبَالٍ فِيهَا مِن بَرَدٍ } قيل: خلق الله في السماء جبالاً من بَرَد، فهو ينزِّل منها بَرَداً وفيه إضمار، أي ينزِّل من جبال البرد بَرَدا، فالمفعول محذوف. ونحو هذا قول الفرّاء لأن التقدير عنده: من جبال برد فالجبال عنده هي البرد. و«بَرَدٍ» في موضع خفض ويجب أن يكون على قوله المعنى: من جبالٍ بردٍ فيها، بتنوين جبال. وقيل: إن الله تعالى خلق في السماء جبالاً فيها برد فيكون التقدير: وينزل من السماء من جبال فيها برد. و«مِن» صلة. وقيل: المعنى وينزل من السماء قدر جبال، أو مثل جبال من بَرَد إلى الأرض  فـ«ـمن» الأولى للغاية لأن ابتداء الإنزال من السماء، والثانية للتبعيض لأن البَرَد بعض الجبال، والثالثة لتبيين الجنس لأن جنس تلك الجبال من البَرَد. وقال الأخفش: إن «مِن» في الجبال و«بَرَد» زائدة في الموضعين، والجبال والبرد في موضع نصب أي ينزل من السماء بَرَداً يكون كالجبال.

Meaning:
(After a long grammatical discussion, he said) ... and Allah send down hails from some mountains of ice which are in sky. And it is not beyond the powers of Allah to make mountains of ice in the sky as he made mountains of stones in the earth.

And according to the Quran, rain also comes directly from heaven/sky.

Quran 2:22:

Who has made the earth your couch, and the heavens your canopy; and sent down rain from heavens

Islam apologists bring this excuse that Arabic word السَّمَاءَ does not only mean 'heaven', but it could also mean 'from above'. Thus, they insist that this verse means only this that Allah sends down rain from above. 

But the problem with this excuse is:

  • Quran & Hadith has nowhere mentioned السَّمَاءَ in the meaning of 'from above', but Islam apologists are taking the meaning out of their own pockets, and it is only based upon their conjecture.
  • None of Sahaba and Muslims scholars of previous centuries ever came up with this idea that السَّمَاءَ means 'from above'.
  • And lastly, Quran has itself closed all the doors for this conjecture of 'from above', while Quran itself defined earlier that it is talking about a physical heaven, which is like a 'canopy' in comparison to a physical earth, which is like a bed. 

From Tabi'un (i.e. 2nd generation of Muslims after Sahaba), we have recorded traditions that rain comes directly from the sweat water sea, which is above the 7th heaven (upon which the throne of Allah is resting). 

Tafsir Durr-e-Manthur (link):

عن الحسن. أنه سئل المطر من السماء أم من السحاب؟ قال: من السماء، إنما السحاب علم ينزل عليه الماء من السماء.

Translation:

It is narrated from al-Hassan: He was asked if rain water comes from heaven or from clouds? He replied: Rain water comes from heaven, and clouds are only a sign, and rain water comes from heaven to clouds. 

عن كعب قال: السحاب غربال المطر، ولولا السحاب حين ينزل الماء من السماء لأفسد ما يقع عليه من الأرض، والبذر ينزل من السماء.

Translation:

Ka'b said: Clouds are only to stop the water from falling. If there are no clouds, then all the rain water will fall on the same place. While the rain water descends from heaven.  

عن عكرمة قال: ينزل الماء من السماء السابعة

Translation:

'Ikrama said: Rain water descends from the 7th heaven.

 

Heaven is SOLID physical material:

Quran 82:1: When the sky breaks apart

Quran 84:1: When the sky is split asunder,

Quran 22:65: And He (Allah) withholds the sky lest it falls on the earth

Quran 21:104: (The) Day We will fold the heaven like (the) folding (of) a scroll for records.

Quran 39:67: And not they appraised Allah (with) true appraisal, while the earth entirely (will be) in His Grip (on the) Day (of) the Resurrection, and the heavens (will be) folded in His Right Hand.

Quran 50:06: Then do not they look at the sky above them - how We structured it and adorned it and not for it any rifts?

Quran 78:19: And the heaven is opened and will become gateways

Quran 81:11: And when the sky is torn away,

Quran 70:8: It shall befall on a Day whereon the sky will become like molten brass,

Quran 15:14: Even if We open a door in the heavens and they ascend through it in broad daylight,