Common Weather Terms Explained

Weather forecasts often use specific terms that are not always explained in everyday reporting. This page explains some of the key concepts commonly used when discussing South African weather.

Cold front

A cold front is a boundary where a cooler air mass moves in and replaces a warmer one. In South Africa, cold fronts typically approach from the south-west and are most common during winter, bringing rain, wind and a drop in temperature, particularly to the Western Cape and southern coastal areas.

Cut-off low

A cut-off low is a pressure system that becomes separated from the main flow of weather systems and can remain stationary or move slowly for several days. These systems are known for bringing prolonged, sometimes heavy rainfall to parts of the country, particularly the southern and eastern coastal regions, and can lead to flooding if rainfall totals are high.

Ridging high

A ridging high refers to a high-pressure system that extends, or ridges, along the south coast of the country. This often brings a change in wind direction and can lead to cooler, moister conditions along affected coastal areas, sometimes with drizzle or low cloud.

South-easter

The south-easter is a strong, persistent wind associated with the Western Cape, especially in summer. It develops when a high-pressure system is positioned to the south of the country, driving wind around its edge. In Cape Town, this wind is well known for its effect on local conditions, including the formation of the distinctive cloud layer over Table Mountain.

Berg wind

A berg wind is a warm, dry wind that blows from the interior towards the coast, often ahead of an approaching cold front. These winds can cause a noticeable rise in temperature and a drop in humidity, and are sometimes associated with increased fire risk due to the dry conditions they bring.

Convective thunderstorm

Convective thunderstorms form when warm, moist air rises rapidly, cools and condenses, building into towering clouds. These are the typical afternoon storms seen across much of the South African interior in summer, and can produce heavy rain, lightning, strong gusts of wind and hail in a relatively short period.

Drought

Drought refers to an extended period of below-average rainfall that leads to water shortages, affecting agriculture, water supply and the natural environment. In South Africa, droughts can affect different regions at different times, depending on rainfall patterns, and may last for a single season or persist over several years.

Why these terms matter

Understanding these terms can make daily or weekly weather forecasts easier to interpret, particularly when trying to understand why certain regions are expecting rain while others remain dry, or why temperatures might suddenly change over a short period. Recognising these patterns also helps in anticipating how weather systems typically develop and move across South Africa.