The unemployment rates rose in 46 of the largest 49 metro areas. Two of the rates showed no change — in Denver and Minneapolis. But only one — in Buffalo-Niagara Falls — showed a decline, dipping to 8.3 percent from 8.5 percent. Some economists said they thought seasonal hiring linked to Niagara Falls tourism factored into the dip.

Among the other bright spots was Bismarck, N.D., which registered May’s lowest jobless rate of 3.5 percent. North Dakota has been helped by the oil business. Bismarck was followed by Iowa City, Iowa, home of the University of Iowa, with an unemployment rate of 3.7 percent, and Ames, Iowa, at 3.8 percent.