A method for operating a memory device includes sensing a change in temperature of the memory device, adjusting a level of a reference current for a read operation, and reading data from memory cells of the memory device based on the adjusted level of the reference current. The level of the reference current is adjusted from a reference value to a first value when the temperature of the memory device increases and is adjusted from the reference value to a second value when the temperature of the memory device decreases. A difference between the reference value and the first value is different from a difference the reference value and the second value.