WASHINGTON — Hiring was surprisingly weak in January for the second straight month, likely renewing concern the U.S. economy might be slowing after a strong finish last year.

Employers added 113,000 jobs, the government said today, far less than the average monthly gain of 194,000 last year. This follows December’s tepid increase of just 75,000. Job gains have averaged only 154,000 the past three months, down from 201,000 in the preceding three months.

Sluggish job growth for a second straight month may reflect what investors and economists have begun to fear: That the U.S. job market is weakening again, along with sectors like manufacturing and retail sales in the United States and abroad. The weakness might also raise doubts about the Federal Reserve’s plans to steadily scale back its economic stimulus this year.

Still, more people began looking for work in January, a sign they were optimistic about finding work. Some found jobs, thereby reducing the jobless rate to 6.6 percent from 6.7 percent. That’s the lowest since October 2008.

Cold weather likely held back hiring in December, economists said, though the impact faded in January. Construction firms, which sometimes stop work in bad weather, added 48,000 jobs last month.

Signs of economic weakness in the U.S. and overseas have sent stock prices sinking. Upheaval in developing countries has further spooked investors.