Weatherwatch: Forecasting’s astrological origins

A 16th-century map of the world derived from observations of the second-century astronomer Ptolemy. Photograph: MPI/Getty Images

Forecasting the weather used to be less scientific and more magical, to the point that practitioners could be accused of witchcraft.

The mathematician and astronomer Ptolemy of Alexandria drew up tables of planetary motions in the second century. Ptolemy was a notable pioneer in astronomy, but went too far in his conclusions about planets influencing our atmosphere. He devised a complex set of calculations to determine their supposed effects on the weather, in a branch of astrology known as astrometeorology.