Factory production in the U.S. unexpectedly declined in January by the most since May 2009, adding to evidence severe winter weather weighed on the economy.

The 0.8 percent decrease atmanufacturers followed a revised 0.3 percent gain the prior month that was weaker than initially reported, figures from the Federal Reserve showed today in Washington. The median forecast in a Bloomberg survey of economists called for a 0.1 percent advance. Total industrial production dropped 0.3 percent even as utility output climbed the most in almost a year.

Assembly lines slowed last month as colder weather tempered production, the Fed said, showing a pause in the momentum of an industry that’s helped bolster the economy. A pickup in capital spending and faster hiring that drives consumer purchases will be needed to spur production gains.