A strong cold front is expected to hit the Western Cape and Namakwa District of the Northern Cape on Thursday, extending into Friday, with officials warning the public and livestock farmers to take care.
The City of Cape Town said the SA Weather Service (SAWS) issued a severe weather warning, with gale force winds and heavy downpours expected to hit the city.
The City's disaster risk management spokesperson Charlotte Powell said on Wednesday that winds could reach up to 70km/h and heavy rain could result in flooding.
"With the wind speed forecast to pick up late tonight, we caution residents to be on alert for possible damage to their homes, as well as trees that may be uprooted and could affect travelling as well as power lines," she said.
"Very rough sea conditions can be expected along the coastal areas, coinciding with the spring tide, so we urge the public to steer clear of these areas."
In a statement, SAWS said heavy rain leading to flooding was expected over the City of Cape Town, Cape Winelands, western parts of the Overberg and West Coast District.
"Due to the vastness of the areas and district municipalities covered, this may put short-term strain on emergency personnel. Heavy downpours during Thursday could result in flash flooding, possibly affecting transport routes and low-lying infrastructure."
Mudslides and rockfalls were possible.
The weather service warned students writing exams in rural communities to be careful while getting to and from school.
Strong to gale force winds and "gusty crosswinds" along the N1 in the Western Cape could adversely affect activities on the highway and rail transport.
"Hazardous driving conditions may result in road accidents along this route. Moreover, high-sided vehicles are at risk of being toppled by intense wind gusts along the route," the statement reads.
Strong winds are expected to persist over the Central Karoo into Friday.
SAWS warned small livestock farmers that the combination of cold, wet and windy weather may kill their animals, unless they were taken to shelter well ahead of time.
The mercury was expected to drop significantly over the high-lying areas of the Western and Eastern Cape, and the southern parts of the Northern Cape.
SAWS said the cold front would exit the country by Saturday. Cold, dry air would spread to the interior of the country, resulting in cold daytime conditions over the Free State, North West province, Gauteng and Mpumalanga.
In an emergency, Cape Town residents should call 107 from a landline or 021 480 7700 from their cellphones.
General faults can be logged with the city's call centre on 0860 103 089, or on the city's website.