Unemployment in Sonoma County ticked up to 4.3 percent in January, driven by seasonal job cuts at local retail stores, restaurants, hotels and construction companies, the state reported Friday.

The county lost 3,400 jobs from December, when the unemployment rate stood at 4.2 percent, the state Employment Development Department reported.

Ben Stone, director of the county’s Economic Development Board, said the job losses reflected seasonal changes in the local economy, not structural weakness.

“With the weather being what it is, yes, there’s a reduction in farming, and I think most of the construction people are not building when it’s pouring rain, so (the uptick in unemployment) is seasonal,” he said.

The figures show the local economy is continuing to expand. Employers have created 5,800 wage and salary jobs over the past year, and the unemployment rate remains well below levels from a year ago, when it was 5.3 percent.

“I think we’re continuing to see recovery and expansion,” Stone said. “It’s a great time to be looking for jobs. ... It’s kind of tough on employers. The complaints I get now are that they can’t find workers. Three years ago, it was the opposite; people were saying ‘We can’t find jobs.’ It’s just kind of the business cycle.”

The county has the sixth-tightest labor market in the state. Only San Mateo, Marin, San Francisco, Santa Clara and Orange counties had lower jobless rates in January.

“Our outlook is quite fair,” Stone said. “Lots of blue sky ahead of us.”

Unemployment declined across the United States in January, falling to 5.7 percent in California and 4.9 percent nationwide.

In Mendocino County, the unemployment rate increased to 6.2 percent in January, up from 6.1 in December but down from 7.2 percent a year ago.

In Lake County, the jobless rate remained flat in January, unchanged from 7.8 percent in December but down from 9.4 percent a year ago.

In Napa County, the unemployment rate declined to 4.8 percent in January, down from 5.1 percent in December and 5.8 percent a year ago.

You can reach Staff Writer Christi Warren at 521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.