While all the smaller islands are only a few meters above sea level, the main island is taller and more sculpted. It is built up of arched rock layers consisting of limestone, sandstone and marble from chalk and tertiary. The land area in the interior of the big island is 50-60 m above sea level. The highest point, 135 m above sea level, is Jabal ad-Dukhan, a rocky hill. Low lying areas in the south and west consist of sand plains and salt marshes. In the north and northwest there is a narrow belt with date palm and fruit orchards, which are irrigated with artificial water from springs and wells; the water is below the seabed but rises through pressure up in Bahrain.
According to COUNTRYAAH, the climate is hot and dry. The average temperature exceeds 29 ° C during May – October and is 21 ° C during December – March. According to BRIDGAT, the rainfall is only about 75 mm per year. The vegetation consists of a few hundred species of desert plants in the interior, while the irrigated areas bear fruit trees and vegetables. Wildlife consists of desert-adapted species, lizards and desert rats, gazelles and capers. There is also a remarkably large number of bird species, many of which are seabirds.
Bahrain has no legislation for environmental protection or nature conservation and no state nature reserves. Three places, including two with a ban on visitors, have been set aside as nature reserves on the initiative of individual emirs.