Does weather forecasting come under the heading of astrology or claiming to know the unseen?

Forecasting
the weather does not come under the heading of astrology or claiming to have
knowledge of the unseen, rather it is based on physical evidence and
experience, and study of the natural laws established by Allaah. The same
applies to knowing the times of solar and lunar eclipses, or when there are
likely to be strong winds and rainfall. 

It says in
Fataawa al-Lajnah al-Daa’imah: The time of solar and lunar eclipses
may be known from calculating the movements of heavenly bodies, from which
it may also be known whether the eclipse will be total or partial. There is
nothing strange about that, because this is not a matter of the unseen for
everyone, rather it is only “unseen” for those who have no knowledge of
astronomy and it is not “unseen” for those who have knowledge of this
science. That does not mean that solar and lunar eclipses are not among the
signs of Allaah with which He instils fear in His slaves so as to bring them
back to their Lord and to obedience to Him.

 It also
says: 

Forecasting
the weather and predicting strong winds and storms or saying where clouds
are expected to form or where rain is likely to fall is based on knowledge
of the natural laws of Allaah. One who has experience of these laws may say
what he expects to happen, without certain knowledge, on the basis of
scientific theories or common experience, so he expects that and predicts it
on the basis of likelihood, not certain knowledge, and he gets it right
sometimes and gets it wrong sometimes. End quote from Fataawa al-Lajnah
al-Daa’imah.  

Shaykh Ibn
‘Uthaymeen (may Allaah have mercy on him) said: The one who speaks of that
which may be worked out by calculations is not a fortune-teller at all,
because there is no element of fortune-telling in that which may be worked
out by calculations. If a person predicts a solar or lunar eclipse, this is
not fortune-telling because it is worked out by calculations. If he says
that the sun will set at a 20-degree angle at such and such a time, this is
not knowledge of the unseen, because it is something that may be worked out
by calculations, and predicting something that can be worked out by
calculation, even if it is in the future, is not regarded as being knowledge
of the unseen, or fortune-telling. 

Is
twenty-four hour weather reporting such as we have now fortune-telling? 

The answer
is no, because it is also based on scientific data which is describing
climatic conditions, because climatic conditions have to do with precise
measurements that are known to them. Thus they may predict that certain
conditions are likely to produce rain or not. That is like the primitive
predication that we make when we see clouds forming, and thunder and
lightning and thick clouds, and we say: “It is going to rain soon.” 

What matters
is that what points to physical phenomena is not knowledge of the unseen,
even if some of the common folk think that these things are matters of the
unseen and say that believing in them is like believing in fortune-telling. 

End quote
from al-Qawl al-Mufeed Sharh Kitaab al-Tawheed. 

See
al-Fataawa al-Kubra by Shaykh al-Islam Ibn Taymiyah (4/424) with regard
to the knowledge of astronomers about the times of solar and lunar eclipses,
the beginning of spring and winter, and other matters that may be known by
means of calculations and are not matters of the unseen. 

And Allaah
knows best.