Suddenly, inflation is running a lot less hot. It could get cooler still in the months ahead.

The Labor Department on Tuesday reported that U.S. consumer prices rose a seasonally adjusted 0.1% last month from October—well short of the 0.3% economists had expected. That put overall prices 7.1% above their year-earlier level, marking the smallest gain since December of last year. Prices excluding food and energy items—the so-called core that economists and policy makers look to for a better understanding of inflation’s trend—rose a smaller-than-expected 0.2% from October and were up 6% versus a year earlier.