- Minimum temperatures may drop sharply again until next week due to a cold front that is moving across the country.
- A front may cause frost in places until the end of the week, and more cold fronts may still occur across the country in the coming weeks.
- Rain patterns are beginning to shift, with lighter rain likely over eastern parts of the summer rain region from the latter part of September.
- Planting time could be busy again this year for the eastern summer grain production areas.
Cold fronts are continuing to move across the country in early spring, although they are beginning to appear more fragmented and are passing south of the country more frequently.
Until 22 September, minimum temperatures may drop below freezing in places in the southern Free State as well as the Eastern Cape, Northern Cape and Western Cape.
“At Barkly East in the Eastern Cape, temperatures could drop to as low as -2°C from 20-22 September, and at Aliwal North to 0°C,” says Johan van den Berg, an independent agricultural meteorologist. “The temperature could also drop to -2°C at Zastron in the Free State.
“In Ceres in the Western Cape, temperatures could drop to freezing, and to as low as 2 °C at Robertson, De Doorns in the Hex Valley and Worcester.”
Temperatures could also approach freezing in the Northern Cape at De Aar and Calvinia. “However, it seems that minimum temperatures in the lower Orange River, where vines are already in a very critical budding stage, will not drop below 5°C.”
Weather models also indicate that minimum temperatures in the Langkloof – in places such as Joubertina and Avontuur – may drop below 5°C and light frosts may occur, especially in low-lying parts.
Frost may still occur in the last week of September, or even later, over southern parts of the Northern Cape and northern parts of the Eastern Cape. “Although sporadic temperature drops are still to be expected, it looks as if rain, rather than further intense cold conditions, will begin to occur over the area north of the Orange River,” says Van den Berg.
Conditions for summer rain improve
With normal rain patterns beginning to develop over the summer rainfall region, conditions for summer rain are beginning to improve, particularly over eastern and southeastern parts of the country.
Rain usually starts to fall over eastern parts from the latter part of September, according to rainfall records. Average September rainfall is about 80mm for Port Shepstone in KwaZulu-Natal and 84mm for Richards Bay. Further east at Dundee it is only 38mm, and at Bethlehem in the eastern Free State 33mm.
“Forecasts until the end of September are that rainfall should be very close to the long-term average. However, it seems as if the rain will be spread over a few days, and fairly light precipitation per rainy day will cause its effectiveness to decrease because it will only result in moisture in the upper soil layers,” says Van den Berg.
“Over smaller areas, however, heavier precipitation could occur, especially over the areas adjacent to the northern Drakensberg and KwaZulu-Natal’s coastal areas.”
Between 10 and 20mm could fall in places such as Bethlehem, Standerton, Bergville, Kokstad, Volksrust, Memel, Newcastle and Underberg. Further west and north, precipitation of less than 20mm is predicted in places such as Delmas, Pretoria, Bothaville, Lichtenburg, Brits, Joubertina and Cradock. For the rest of the country, less than 10mm is expected.
As far as the winter rainfall region is concerned, from 18-22 September between 10mm and 20mm is predicted over the Garden Route as far as Grabouw in the Western Cape. Very little rain is expected over the Winelands district and the West Coast.
Planting time
Forecasts indicate light precipitation over KwaZulu-Natal, the Eastern Cape, the eastern Free State and Mpumalanga during the first part of October.
“Conditions should improve in the second part of October over these areas, with heavier rain likely to occur,” says Van den Berg.
“Projections are that before the middle of October there will not be sufficient rain everywhere in the eastern summer grain production areas to cultivate and plant fields; full-scale plantings will probably only be possible in the latter part of October.”
Van den Berg says the planting window for the eastern areas can be limited as plantings must be completed by the middle to the end of November for optimal production. “For the central to western summer grain areas, sufficient planting rain should not occur until mid-November. However, this will leave enough time for planting, which can take place until the end of December.”
Over the eastern summer grain production areas, rainfall may trend from normal to above normal from the latter part of October to early February, and over the central to western parts normal to above normal from November to March.
“A dry period is possible around February and March 2025 over the eastern areas,” says Van den Berg. “The chances of a long midsummer drought are slim across the central to western production areas. However, dry periods this year will again depend heavily on the occurrence of tropical cyclones in the Indian Ocean.”
