Food prices rose at a slower rate in June.

That overall metric catches big declines in gas prices and a few other products that could prove ephemeral, which is why policymakers closely watch a different measure: the change in prices after stripping out food and fuel costs. That measure, known as the core index, offered news that was even better than what economists had expected, sending stocks higher as investors bet that the news would allow the Fed to raise interest rates by less than they otherwise might have.

The core index climbed 4.8 percent compared with the previous year, down from 5.3 percent in the year through May. Economists had forecast a 5 percent increase. And on a monthly basis, the core index climbed at the slowest pace since August 2021.

“This is very promising news,” said Laura Rosner-Warburton, senior economist and founding partner at MacroPolicy Perspectives. “The pieces of the puzzle are starting to come together. But it’s just one report, and the Fed has been burned by inflation before.”

Slower inflation is unquestionably good news, because it allows consumer paychecks to stretch further and inflicts less pain at the gas pump and in the grocery aisle. But Federal Reserve officials are still trying to assess whether the cool down is likely to be quick and complete. They do not want to allow price increases to linger at slightly elevated levels for too long, because if they do, consumers and businesses could adjust their behavior in ways that makes more rapid inflation a permanent feature of the economy.

Given that, they may be cautious in interpreting the news. Officials have signaled in recent weeks that they are likely to raise interest rates at their July 25-26 meeting.

Ms. Rosner-Warburton said she thought a July move was still likely, but that the fresh inflation data could lay the groundwork for “a more extended pause” after. She added that a cooling in car prices and slower rent increases should keep the moderation in inflation underway, and she forecast that the Fed would not raise interest rates again this year following the July change.

The June inflation slowdown came as a few key products and services posted steep price declines. Airfares fell 8.1 percent compared with the previous month, and used cars and trucks were down 0.5 percent. New vehicle prices were flat compared with May.

Not all of those changes will necessarily last: Airline tickets, for instance, are not expected to continue to decline as sharply as they did in this report. But for the Fed, there were other encouraging signs that the cool-down is broad enough to prove sustainable.

For one thing, the cost of housing as measured by the Consumer Price Index — which relies on rent prices — is coming down sharply. That is expected to continue in coming months. An index tracking the rent of primary residences slowed to a 0.46 percent change in June, the weakest increase since March 2022.

Car prices are also cooling. After years in which semiconductor shortages and other parts problems limited supply, making it hard to meet booming demand, discounting is making a comeback on car dealer lots. Inventories are rebounding, and consumers have a less voracious appetite for new cars in particular.

“It’s different from the past couple of years, and even different from the fall,” said Beth Weaver, who runs a Buick GMC car dealership in Erie, Pa. “Interest rates have certainly weighed on demand.”

And more broadly, price increases for a basket of services excluding energy, food and housing costs — a metric that the Fed watches very closely — continued to slow in June.

But in spite of all of the recent progress, inflation remains above the rate of increase that was normal before the 2020 pandemic. And the economy still retains momentum, with strong job and wage growth, which could give companies the wherewithal to keep raising prices. That is why Fed officials are hesitant to say they have won the battle against inflation.

“It would be a mistake” to “declare victory” too early, Loretta Mester, the president of the Federal Reserve Bank of Cleveland, said on a call with reporters this week.

The Fed officially targets 2 percent inflation on average over time, though it defines that goal using a separate inflation measure, the Personal Consumption Expenditures index. That gauge is also slowing notably, and its June reading is scheduled for release on July 28.

Even if central bankers are likely to interpret the slowdown cautiously — cognizant that price increases have slowed and then accelerated again before — many commentators welcomed the fresh data point as the latest sign that the economy may be able to slow gently.

Officials at the Fed have been trying to engineer a “soft landing” in which inflation slows gradually and without requiring a big jump in the unemployment rate. Interest rates increases work partly by slowing the job market and cooling wage increases, so the Fed’s fight against inflation and the strength of the labor market are closely tied.

“The sustained decline in inflation is encouraging news for the U.S. labor market outlook,” Julia Pollak, chief economist at ZipRecruiter, wrote in response to the fresh release. “It increases the likelihood that the Fed will be able to pause rate hikes after one final July increase, and gradually lower rates through 2024.”