The state covers 984000 square kilometres most of which is sparsely settled hinterland. 99% of the population of nearly 1.5 million lives south of the 32nd parallel, most in the city of Adelaide which is located near the coast in the Eastern shore of the Spencer Gulf. 1/3rd of the state’s land mass has no significant economic use and receives little rain. Another 1/2 is suited only to light grazing. The settled areas of the Yorke, Fleurieu Peninsulas, and the South Eastern area close to the Victorian border receive the only significant rain, making South Australia the driest state in Australia. Poor rainfall and long periods of sunshine are bad for farmers but great for divers. The weather is often sunny and bright making it easy to plan outdoor activities. The temperature never falls below 7 degrees Celcius along the coast and enjoys a mean Summer temperature of 25 degrees. The hot days do whip up dangerous sea breezes in the October-May period that can be hazardous for late returning boatmen. Adelaide also experiences the ‘Gully Wind’ that can whip up strong Easterly gusts in Summer. Early starts are required. The prevailing winds are SE in Summer and Westerly in Winter.
There are 3700 kilometres of coastline, making it nearly as large as New South Wales and Victoria combined, and slightly larger the excellent diving coasts of Tasmania. Much of its coastline is moderately inaccessible to the main population centre and most of the diving activity is focused on the reefs, wrecks and jetties close to Adelaide. The unusual shape of the state’s coastline means that relatively long land journeys are required to reach the more adventurous dive sites. On long weekends divers leave Adelaide in droves looking for something a bit more adventurous on the more distant sites around the Yorke and Eyre Peninsulas, around Kangaroo Island and the South East.
South Australia covers the area from 129 degrees East to 3km West of 141 degrees east and is 1201 kms across. SA waters have a low nutrient rating generally, but low temperatures off Ceduna and the South East in Summer mean more plankton and larger species of fish, more crays than in the shallower areas of the major gulfs. Off the South East and Southern Yorke Peninsula a lot of turbulence means more food for fish. Rocky bottoms also provide good holding points for a variety of marine life.