JOHANNESBURG, Sept 28 (Reuters) - South Africa's rand weakened in early trade on Wednesday, as the dollar soared after Chicago Fed President Charles Evans reiterated a hawkish stance towards inflation.

At 0716 GMT, the rand traded at 18.1875 against the dollar, 0.93% weaker than its previous close.

The dollar index against a basket of major currencies rose about 0.4% to 114.600.

The dollar is scaling fresh two-decade highs nearly every day, which is keeping emerging market currencies on the back foot, economists at ETM Analytics said in a note.

"The moment the (now extremely overvalued) USD loses its topside impetus – whether it be due to a shift in Fed rhetoric or normalisation of risk sentiment stemming from positive developments in Europe or China – the ZAR is poised to capitalise," ETM Analytics said.

On the stock market, the Top-40 and the broader all-share indexes fell more than 2% in early trade.

The government's benchmark 2030 bond was weaker in early deals, with the yield up 9.5 basis points to 10.875%. (Reporting by Anait Miridzhanian; Editing by Alex Richardson)