The Cape Doctor is a strong, persistent south-easterly wind that affects the Cape Peninsula and Table Mountain area, primarily during the summer months (September to March). 

It is called the Cape Doctor because it was historically believed to clear the air of pollution, disease, and the smells of Cape Town, acting as a cleansing force over the city and peninsula. 

The Cape Doctor is driven by the South Atlantic High (also known as the South Atlantic Subtropical High or the St Helena High) which intensifies and shifts southward during summer, producing a tight pressure gradient over the Cape Peninsula and driving strong south-easterly winds onto the coast. The wind is typically associated with clear skies and excellent visibility, as it sweeps away any cloud and haze. However it can produce the famous tablecloth effect on Table Mountain, where moist south-easterly air cools orographically over the mountain and a persistent layer of orographic cloud caps the summit while the surrounding areas remain clear. 

The Cape Doctor can reach gale force (35+ knots) and is a well-known hazard for aviation and maritime operations in the Cape Town area. It is distinctly a summer phenomenon and is not associated with cold north-westerly winter rains, warm berg-type descending winds, or autumn coastal fog.

A strong south-easterly wind during summer usually accompanied by clear skies → CORRECT. The Cape Doctor is precisely defined as a strong to gale-force south-easterly wind affecting the Cape Peninsula predominantly in summer (September to March), driven by the South Atlantic High intensification. It is associated with clear skies and excellent visibility at surface level, while producing the famous orographic tablecloth cloud over Table Mountain. 

A cold north-westerly wind during winter bringing heavy rainfall → INCORRECT. Cold north-westerly winds in winter are associated with cold front approaches from the South Atlantic, bringing the winter rainfall that characterises the Western Cape Mediterranean climate. This is a real weather phenomenon but is called a north-westerly or nor-wester, not the Cape Doctor. The Cape Doctor is south-easterly and occurs in summer.

A warm berg wind descending from the Hottentots Holland mountains → INCORRECT. Berg winds do affect the Western Cape, descending from the interior plateau and the Hottentots Holland and Du Toitskloof ranges. They are warm, dry, and offshore. However they are not called the Cape Doctor. The Cape Doctor blows from the south-east onto the land, not offshore. 

A persistent coastal mist that develops during the autumn months → INCORRECT. Coastal mist and advection fog do affect the Cape Peninsula area, particularly when warm moist air from the ocean moves over the cold Benguela Current along the west coast. However this phenomenon is not the Cape Doctor. The Cape Doctor is a wind, not a fog or mist, and it occurs in summer not autumn.