Sion is a neighbourhood of Mumbai. The Marathi name for Sion is Sheev which means boundary or limit. Mumbai as we know it now didn’t exist then. In the 17th century the village formed the boundary between Mumbai and Salsette Island. The British named it marking the end of the city. The name remained even after Mumbai was joined to the Salsette and extended up to Mulund. However now Sion is not the end of the city. One of the local historical places in Sion is a hilltop garden commonly known as Sion Fort or Sion Killa in native language Marathi.
There is significant rainfall throughout the year in Sion. Even the driest month still has a lot of rainfall. Thisclimate is considered to be Cfb according to the Koppen-Geiger climate classification. In Sion, the average annual temperature is 9.5 °C. Precipitation here averages 692 mm.
In 1543, the Portuguese took possession of the islands of Bombay by force, naming it Sion. The Portuguese gave the Jesuit priests the sole ownership of some of these islands. The Jesuits then built a chapel on the hill near the present-day railway station and named it after Mount Zion (Sion) in Jerusalem. Its in South Mumbai.