WASHINGTON — Unemployment rates rose in nearly all large U.S. cities in June as college graduates and many of those still in school began searching for jobs.

The Labor Department said Tuesday that unemployment rates rose in 347 large metro areas in June compared with the previous month. They fell in 12 and were unchanged in 13. In May, rates fell in 109 cities and rose in 243.

Unlike the national figures, the metro unemployment data are not adjusted for such seasonal changes. Many of the cities with significant rate increases have large universities where students graduated in June and began looking for work. And many university workers are temporarily unemployed in the summer when the academic year ends.

The city with the nation’s lowest unemployment rate was Bismarck, N.D, where the rate was 2.8 percent.

Yuma, Ariz., reported the highest rate at 31.8 percent. Yuma has a heavy population of migrant farm workers.

Among the 49 cities with more than 1 million in population, Detroit had the highest unemployment rate at 10.3 percent. That’s up from 9 percent in May.

The unemployment rate in Minneapolis was 5.1 percent, the lowest among the large cities.