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.