Memory controller for performing read operation and operating method thereof

A memory controller for controlling a memory device comprising a plurality of memory cells, the memory controller comprising:

• a history voltage storage unit configured to store information on a plurality of history average voltages, each representing an average voltage of each of a plurality of threshold voltage distributions for the plurality of memory cells;
• a read operation control unit configured to control the memory device to perform a read operation on a memory cell selected from among the plurality of memory cells;
• and
• a read voltage setting unit configured to, when a read operation performed under the control of the read operation control unit using a read voltage fails, determine a first cell count representing a number of cells measured to have a specific value based on the read voltage, determine a second cell count representing a number of cells predicted to have the specific value based on the read voltage through a first arithmetic operation performed based on an average voltage that is adjacent to the read voltage and selected from among the plurality of history average voltages, adjust a level of the average voltage through a second arithmetic operation performed based on a difference between the first cell count and the second cell count, and adjust a level of the read voltage based on the adjusted level of the average voltage.