This article was written by the South African Weather Service (SAWS) National Forecasting Centre’s Stella Nake, Ezekiel Sebego, Puseletso Mofokeng, Lehlohonolo Thobela and Rudzani Malala.
At least two cold frontal systems are expected to develop early next week starting from the 19-23 May 2025.
The South African Weather Service (SAWS) said it is closely monitoring these systems with the view to issue out weather impacts associated with the cold fronts across parts of the Western Cape province on Monday, 19 May through to Wednesday, 21 May, when strong winds and rough sea conditions are expected to spread to the south coast and the Eastern Cape.
A cold front will make landfall over the south-western parts of the country, on Monday.
This is expected to bring wet, cold, and windy conditions over the western parts of the Western Cape.
While this system will not be intense, it serves as a precursor to the more significant weather system that will follow the next day.
On Tuesday, 20 May, weather conditions will spread to the east, affecting the Namakwa District of the Northern Cape and the Eastern Cape.
Rainfall accumulation is expected to range between 15 to 25 mm, with a possibility of reaching 30 to 50 mm in mountain areas.
The persistent and continuous rainy conditions may lead to localised floods, particularly in areas with poor drainage and low-lying regions. Strong and gusty westerly to north-westerly winds, with wind speeds averaging between 55 and 65 km/h, are expected across the Western Cape, Northern Cape, and the Eastern Cape more especially over the interior.
Possible impacts might result in outdoor activities being disrupted with a high likelihood of localised damage to infrastructure, uprooted trees, increased traveling time on the roads, problems for high sided vehicles, especially along the national routes through the provinces as well as disruptions to power lines.
For maritime operators and coastal residents, westerly to north-westerly gale-force winds (65-75 km/h) are expected along the coastline, particularly from Alexander Bay through to Plettenberg Bay. These high winds will result in very rough seas on Tuesday and Wednesday, leading to sea conditions that could impact small vessels and coastal activities. There is also a possibility of abnormal waves along the south-eastern coast, with wave heights of 5,0 to 6.5 m, occasionally peaking at 7.0 m, with a 10 seconds wave period on Wednesday.
In addition, freezing conditions are expected to drop considerably, creating conditions favourable for some snowfall over high-lying areas and a general drop in temperatures. These very cold conditions are expected to spread to the central and the eastern parts of the country from Tuesday late evening, persisting until Friday morning, 23 May 2025.