The Berg Wind is a hot, dry, offshore wind that affects the western and southern coastal regions of South Africa, most frequently in late winter and spring (August to October).

The Berg Wind originates when a strong anticyclone (high-pressure system) establishes itself over the interior plateau of southern Africa, particularly over the Highveld region at elevations above 1500 m. Air flows outward from this high-pressure centre and descends off the interior plateau toward the lower coastal regions. As the air descends, it is compressed and warms adiabatically at the dry adiabatic lapse rate of approximately 3°C per 1000 ft of descent. Since the interior plateau is already elevated well above sea level, the descending air can warm by 15°C or more before reaching the coast.

The result is a very hot, dry, gusty offshore wind at the coast, sometimes reaching temperatures above 40°C.

A strong high-pressure system over southern Africa → CORRECT. The Berg Wind is generated when a strong anticyclone over the southern African interior plateau drives air outward and downslope toward the coast. The descending air warms adiabatically and loses moisture, arriving at the coastal strip as a hot, dry, gusty wind. 

A deep tropical depression moving south from the equator → INCORRECT. Tropical depressions are low-pressure systems associated with convergent, rising air and significant precipitation — the meteorological opposite of the descending, warming, drying air flow that produces the Berg Wind. A tropical depression moving south could affect South African weather in other ways but is not the cause of Berg Wind events.

A cold front approaching the Western Cape from the South Atlantic → INCORRECT. Cold fronts approaching from the South Atlantic produce northwesterly winds and rainfall ahead of the front. While cold front approach can temporarily enhance Berg Wind conditions by modifying the pressure gradient, the cold front itself is not the cause of the Berg Wind. The cold front passage typically ends Berg Wind conditions by introducing cooler moist air from the south.

A strong sea breeze developing along the Namibian coastline → INCORRECT. Sea breezes are local thermal circulations driven by the temperature differential between land and sea surfaces during daytime heating. They are low-speed, shallow, onshore winds from sea to land. The Berg Wind is an offshore (land to sea), hot, dry, high-speed wind. These are physically opposite phenomena.