Brontoscopy, a branch of ceraunoscopy, is divination by listening to the sound of thunder.
Brontoscopy was prominent amongst the Babylonians, Etruscans, Indians and Ancient Romans. In the Middle Ages it was believed that thunder and lightning in winter was a portent of war, summertime floods, or the death of a important person living within a 20 miles radius.
Ancient Roman augurs (priests who specialized in the interpretation of auspices, the movement of birds, or sometimes other animals) believed that thunder from the left was a lucky omen or happy ending. Thunder from the right was a bad omen. Thunder on Sunday indicated the death of aan educated or wise man, such as a judge, general, or scholar. Thunder on Monday indicated the death of a woman. Thunder on Tuesday or Thursday was a good omen, indicating plenty of grain (especially wheat, which the Romans called corn, not to be confused with maize) and sheep. Thunder on Wednesday indicated the death of a prostitue or beggar or some other more general kind of bloddshed. Thunder on Friday indicated the murder of a great man. Thunder on a Saturday indicated widespread death, especially by plague.
Deities associated with the practice