Summer is worse than winter for flight delays, according to the fifth annual The Best and Worst Airports for Summer Travel Delays, a report from MagnifyMoney.com, a personal finance site, with 52 percent of airports experiencing more delays in summer than winter. Frequent culprits were congestion and weather. The report also found that summer delays are increasing, with 54 percent of airports having worse arrival rates in 2017 than they did in 2016, with an average on-time rate across all airports of 76.1 percent, versus 76.5 percent. The six worst airports for on-time arrivals in summer were Newark-Liberty, LaGuardia, San Francisco, John F. Kennedy, Boston Logan and Chicago O’Hare. The best were Honolulu International, Salt Lake City, Detroit Metro, Norman Y. Mineta San Jose International, Minneapolis-St. Paul, Portland International (Oregon), Seattle-Tacoma and Phoenix Sky Harbor.