SEOUL, June 4 (Reuters) - South Korea's consumer inflation slowed for a second straight month in May to a 10-month low, official data showed on Tuesday, coming in lower than market expectations.

The consumer price index (CPI) in May stood 2.7% higher than a year earlier, slower than a rise of 2.9% in April and a gain of 2.8% tipped in a Reuters survey of economists. It was the slowest annual increase since July.

The index rose 0.1% over the month, according to Statistics Korea, after no change in April and compared with a 0.2% rise expected by economists. (Reporting by Jihoon Lee; Editing by Jacqueline Wong)