At 1010 GMT, commercial banks quoted the shilling at 90.35/45 to the dollar, a touch weaker than Monday's close at 90.25/45 to the dollar.
Ian Kahangara, a trader at National Bank of Kenya, said that over the past two days some traders have sold dollars to boost their shilling positions due to a small liquidity crunch amid thin trading volumes.
Traders said most businesses and non-governmental organisations that need to exchange foreign currency closed down for the year last week.