WASHINGTON—The Federal Reserve’s preferred measure of inflation rose last month to the strongest reading in more than two years, providing fresh evidence of firming prices a day before policy makers meet to discuss the path of interest rates this year.

The personal-consumption-expenditures price index advanced 0.2% in December from the prior month, the Commerce Department said Monday. The measure of consumer inflation rose 1.6% from a year earlier, a 12-month increase last seen in September 2014. The reading was last higher...