The cold front from Cape Town will spread into other provinces, SA Weather Services said on Saturday.
Forecaster Edwin Thema said there will be rough seas from Alexander Bay in the Northern Cape and Port Alfred in the Eastern Cape.
The Free State and KwaZulu-Natal will also be affected.
"Snow fall can be expected over high grounds in the Western Cape, parts of the Northern Cape and spreading to the high ground of the Eastern Cape into Lesotho. The Free State can expect light snowfall," Thema said.
The cold front is also expected to pass through Gauteng and Limpopo on Sunday.
"[It will bring] showers to the central and southern parts of the county and then very cold conditions in the high grounds of the Western Cape, Eastern Cape, Northern Cape, Lesotho, the high grounds of KwaZulu-Natal and Mpumalanga."
Earlier on Sunday, the Cape disaster management centre said it was on high alert following reports of flooding in several townships.
Phola Park, Rasta Camp, Masiphumelele, Lotus Park, Wallacedene, Happy Valley and Phillip informal settlements were all affected.
Several houses lost their roofs in the high winds.
Emergency workers provided blankets and parcels to those affected.
Chapman's Peak Drive has also been closed off since Friday.