two scientific miracles puzzled me?

[truth search]

hi everyone, 
muslims claim that there are many scientific miracles in the quran, i found that the most of them are false, but there are two miracles that i didn't found any proof that they are false:
the first is the the aya 48 of the surat 30 that said:
"It is Allah who sends the winds, and they raise the clouds."
the scientist of meteorology until 19th century didn't know that the winds have a role in the raising of clouds, so how mohamed before 1400 years knew that?


the second, mohamed said that: 
"rainfall in one year is no less (in amount) than that falling in another year, it is only allah distributes the rain"
the science proved in our days that 505000 cubic kilometres of water falls as precipitation each year.
how mohamed before 1400 years knew that ?

thank you and i'm sorry if my english is not good.

The second one is wrong.  The earth has changed a lot in the billions of years of it's existence.  There's been ice ages, changes in the suns brightness in relation to the earth.  The formation of oceans on the earth was due enormous amounts of rainfall after the atmosphere began to cool and water could actually exist on earth.  It also says on Wikipedia that rain precipitation is changing globally due to global warming.

2nd point.  There is no scientific proof that I have found that exactly 505000 cubic kilometres of water falls each year.  I've seen on Wikipedia and other sites it says that is an approximate amount  .  The science wouldn't say it was approximate if it was proof that exactly that much falls.  Plus it's approximately dealing with cubic kilometres which isn't small amounts.  And as I said in my previous point I'm nearly certain this is since the existence of weather records or at least since humans have inhabited the Earth which is a miniscule portion of the entire earths history.

3rd point.  It doesn't say which rain, where, or what type of rain.  The science hypothesizes that some planets may have iron rain, some neon rain.  (neon rain or iron rain would be such a fucking cool name for a band, just a thought.)

i think that you are right because there are many scientific errors in the quran.
but the problem that confused me: if mohamed is the only man that observate these two phenomena or not?
because muslims could say that mohamed is the only man who said that the wind have a role in raising clouds and that there no year is rainfull than another  , so, it can't be an observation. because if it is an observation many others will have the same observation.
it's true that we can responding them by proving that there are many scientific errors in the quran.
but if we prove that there are another men that observate these two phenomena, we wil refute their claim completely.
so, i began my research, and i found that the romans philosoves thinks that the "Wind transported water to the clouds":
http://greenoakschurchofchrist.weebly.co..._cycle.pdf

Talking about the second phenomena, it just simply isn't true.  The amount of rainfall on earth isn't exactly the same each year.

Second of all the reasoning behind the miracle not being true in this case is very faulty.

How could Muhammad have observed that rainfall is the same each year globally before he even knows that America exists?

I agree it's not a miracle, BUT only on the basis that the amount of rainfall each year on earth isn't the same, but I disagree with the reasoning that it's not a miracle because Muhammad just observed this.

the wiki says:
" Approximately 505,000 km3 (121,000 mi3) of water falls as precipitation each year" 
it's completely false?