Airline delays and cancellations are up slightly from last year’s peak travel season.

The U.S. Department of Transportation said Thursday that flights on the nation’s largest airlines arrived on time 77.7 percent of the time in August. That is down from 78.8 percent in the same month last year, although it is better than July.

The 14 airlines covered in the government report canceled 1.2 percent of their U.S. flights in August, up from 1.0 percent a year earlier.

The airlines blame bad weather for an increase in delays and cancellations this year. The first six months of 2014 were the worst for delays since 2008.

Hawaiian Airlines, which benefits from good weather on much of its route network, held its usual place atop the rankings. Delta Air Lines was best among the largest carriers. American Airlines and one of its regional-flying subsidiaries, Envoy Air, had the worst on-time ratings. American did not immediately respond to a request for comment.

Only one domestic flight was delayed on the tarmac for more than three hours in violation of federal rules — a Republic Airlines plane scheduled to fly Aug. 12 from Washington’s Reagan National Airport to Columbus, Ohio. Such delays can bring fines. Nearly 300 flights were delayed more than two hours, which is permitted under the rules.

Virgin America ranked best at handling baggage; Envoy had the highest rate of lost, damaged, delayed or stolen bags — nearly twice as high as any other airline.

Southwest Airlines had the lowest rate of consumer complaints to the government. Frontier Airlines had the highest.