Jupiter rules Sagittarius and Pisces, is exalted in Cancer, in detriment in Gemini and Virgo and in fall in Capricorn. Ptolemy gives it a temperate, warm and moist nature, and it is the greater benefic and a planet of the diurnal sect. Its orbital period of just under twelve years means it spends roughly a year in each sign, which made it a natural marker of the year in several traditions: Chinese astronomy called it the Year Star, Suixing, and tracked it through twelve stations, and the twelve-year animal cycle is generally traced to that period. Its natural significations are increase, law, religion, teachers, judges, foreign lands, wealth honourably got, the liver, and abundance in general. The classical texts warn that excess is its characteristic failure, since increase without limit is not a benefit.
Ptolemy's Tetrabiblos, part of the Hellenistic synthesis of roughly the first century BCE to the second century CE, explains Jupiter's temperate, warm and moist nature by a reasoning distinct from the pattern used for the other planets, holding that because its heating power outweighs its moistening one it produces fertilising winds, a specifically meteorological justification rather than a simple proximity argument. Jupiter's standing as the most consistently fortunate of the seven bodies is far older than that Hellenistic formula, however, reaching back to Babylonian celestial omen-reading of perhaps 1000 BCE, where its steady, comparatively predictable path made it a marker of stability and good order in state-level omens long before the personal, chart-based reading of a Greater Benefic was built on top of that older observational tradition.