South Africa's rand weakened against a stronger dollar on Monday, as investors awaited a central bank decision on monetary policy later this week.

At 0635 GMT, the rand traded at 18.2050 against the dollar, 0.26% weaker than its previous close.

The dollar index, which measures the currency against six major rivals, was up more than 0.2% at 103.20.

"Volatility in the rand remains the order of the day, although the local unit did perform a little better last week, at least against the dollar," ETM Analytics said in a research note.

The South African Reserve Bank (SARB) will announce its rate decision on Thursday, with markets expecting a 25-basis-point hike.

The government's benchmark 2030 bond was slightly stronger in early deals, with the yield down 1 basis points to 9.925%. (Editing by Bernadette Baum)