China's yuan rebounded from the prior session's six-week low on Tuesday as a dollar rally lost momentum on renewed doubts of a near term rate rise by the US Federal Reserve. In Shanghai, the People's Bank of China set the midpoint rate at 6.6812 per dollar prior to market open, firmer than the previous fix at 6.6856. Spot yuan opened at 6.6811 per dollar and was changing hands at 6.6777 at midday, 61 pips stronger than the previous close. On Monday, it hit its weakest level since July 20. The offshore yuan was trading 0.19 percent weaker than the onshore spot at 6.6901 per dollar.