At 1530 GMT, the rand traded at 18.3525 against the dollar, 1.12% weaker than its previous close.

The Fed is expected to deliver another 75-basis-point rate hike after the conclusion of its policy meeting on Wednesday.

South Africa's trade surplus widened to 19.70 billion rand ($1.07 billion) in September from a revised surplus of 6.20 billion rand in August, data from the revenue service showed on Monday.

The country's private sector credit in September rose 9.74% year-on-year after rising by 7.86% in the prior month, according to central bank data.

On the Johannesburg Stock Exchange, the Top-40 index closed 0.58% higher, while the broader all-share index ended up 0.43%.

The government's benchmark 2030 bond was weaker in afternoon deals, with the yield up 12 basis points to 10.860%.

($1 = 18.3565 rand)