At 1434 GMT, the rand traded at 18.7450 to the dollar, about 0.4% weaker than its previous close.
The dollar last traded down about 0.06% against a basket of global currencies, but was still set for a strong weekly gain.
The rand had jumped last week as risk sentiment improved after the Federal Reserve left interest rates unchanged.
On Thursday, Fed Chair Jerome Powell said that further interest rate hikes may be needed to bring inflation within the U.S. central bank's target range.
"(Emerging market) currencies have all given back a large part of recent gains as the rate hike fears and fresh global growth concerns dampen risk appetite," said Andre Cilliers, Currency Strategist at TreasuryONE.
"Fresh data releases over the next few weeks will be critical to what the Fed will likely do at its next FOMC meeting," he added.
Like other risk-sensitive currencies, the rand often takes cues from global factors, such as U.S. monetary policy, in the absence of local drivers.
On the Johannesburg Stock Exchange, the blue-chip Top-40 index was down about 1.4%.
South Africa's benchmark 2030 government bond was weaker, with the yield up 5 basis points to 10.390%.
(Reporting by Tannur Anders and Nellie Peyton, Editing by Tomasz Janowski and Angus MacSwan)
