Our ancestors have been attempting to predict it since 650 BC.
"Everybody talks about the weather," an aphorism attributed to Mark Twain goes, "but nobody does anything about it." It's not from lack of trying: Our ancestors have been attempting to do something about the weather -- or at least predict it -- since 650 BC, when Babylonians based their prognostications on cloud patterns.
Without accurate instruments or a way to rapidly communicate measurements, however, early weather forecasting remained mostly a matter of aphorisms. Variations of "Red sky at night, sailor's delight; red sky at morning, sailor take warning" pop up in the Bible (Matthew 16:2-3) and in Shakespeare's Venus and Adonis.