The American economy slowed drastically in the first quarter of 2014, as wintry weather depressed corporate spending and housing sector activity, while weak exports and smaller additions to inventories by businesses also held back growth.

At an annualized rate of 0.1 percent, the pace of expansion in January, February and March was the weakest since the fourth quarter of 2012, when output also barely grew. It also represented a sharp deceleration from the level of growth recorded in the second half of 2013, when the economy expanded at a 3.4 percent rate.

The first-quarter pace also fell well short of the 1.2 percent rate of growth expected by Wall Street economists before the Commerce Department announcement Wednesday morning.

Still, most economists expect that many of the headwinds evident in the first quarter will fade over the course of 2014, and the growth rate will return to a range between 2.5 and 3 percent. In addition, Wednesday’s report is the first of three estimates of growth by government statisticians, and the final figure could ultimately be revised substantially in either direction.

In some recent quarters, inventory swings have had an outsize effect on the overall growth number, and that was the case again in the first few months of 2014. But much of the first-quarter weakness tied to stockpiles is payback from huge inventory gains in the second half of 2013, rather than a fundamental sign of fragility.

The weakness in inventories reduced the growth rate by 0.6 percentage point, while weaker exports shaved 0.8 percentage point off the number. By contrast, exports added nearly added a full percentage point to output in the fourth quarter of 2013.

Even if growth does pick up later this year, the rate will still most likely be below the postwar average of just over 3 percent, said Dan North, chief economist at Euler Hermes North America, a larger insurer.

“We’ve been living in sub-3 percent land, and people have gotten used to that as the new normal,” Mr. North said in an interview before the Commerce Department announcement. “But it’s not. It’s anemic.”

Even as businesses pulled back, consumer spending actually remained reasonably healthy, rising 3 percent.

Wednesday’s economic data kicks off a busy few days for economists and investors. Later Wednesday, policy makers at the Federal Reserve will wrap up a two-day meeting, and are expected to announce another $10 billion reduction in monthly bond purchases by the central bank.

On Friday, the Labor Department will announce the latest figures on the job market in April. The consensus calls for a jump in payrolls of 215,000, with the unemployment rate falling by 0.1 percent to 6.6 percent.

Indeed, on Wednesday, the payroll processor ADP said American businesses increased hiring in April, adding 220,000 jobs in April, the most since November and up from 209,000 in March. The ADP numbers cover only private businesses and often diverge from the government’s more comprehensive report.

If the government’s actual payroll gain meets or exceeds the consensus, it would be the best month for hiring since November, and also echo some other more positive signs for the economy in recent days, like healthy consumer confidence and strong orders for durable goods.