His initial flight was canceled because of storms, and the subsequent flight — on which he managed to get the last open seat — was first delayed and then rerouted around a patch of stormy weather, more than doubling the length of a one-hour flight.
Even with the detour, Mr. Prest said, it was a rough ride. “Because my other flight had been canceled, I was in the very last seat,” he said. “It was like driving down a bumpy dirt road in a car.”
Storms that move eastward from the Midwest, particularly between 3 and 7 p.m., tend to wreak the most havoc on flight schedules.
“The issue is they move in lines, generally west to east, and they generally move right through the Ohio Valley, which is probably the routing of 40 percent of the east-west traffic in the U.S.,” said Robert W. Mann, an airline industry consultant.
“As those lines of thunderstorms move, they basically block traffic,” he said. “They’re strong enough to go up to very high altitudes, sometimes up to 50,000 feet, and you’re not going to outfly that.”
The hub-and-spoke systems used by the major air carriers can make the problem worse. Not only are many major hubs in thunderstorm-prone locations, but connecting-flight delays can have a domino effect. That is one reason travelers might have weather-related flight delays even if the sun is shining at their origination and destination cities.
The need to give rough weather a wide berth can also lead to delays. Airlines avoid flying through storm cells and fly around volatile weather, though the distance from the storm depends on its severity.
“The wind is one of the most important issues,” said Bijan Vasigh, professor of economics and finance at Embry-Riddle Aeronautical University. “Wind shear is one of the most dangerous things,” he said, referring to an abrupt shift in wind speed or direction.
The real issue with wind shear, said Mr. McKone of L.E.K. Consulting, is “if it gets down near the taxiway.” Wind shear during landing “can be quite a problem because you’re often slowing the plane down to a pace where it’s very difficult to recover,” he said.
A single storm can disrupt up to 100 flights for a large carrier, and these disruptions can be expensive.
“We absorbed $125 million pretax loss from the operational disruption following severe storms that hit Atlanta in early April,” the chief executive of Delta Air Lines, Ed Bastian, told investors on the airline’s most recently quarterly earnings conference call. Delta has 25 meteorologists on staff who create weather forecasts, with particular focus on its hub airports in the United States.
Scheduling around storms is a complicated process involving not only the affected airlines but also air traffic control, and must take into account everything from the number of flights and passengers affected to limits on flight crew hours, gate availability and tarmac delay rules that airlines can be fined for violating.
“We do have a tool that will optimize our best choices, but we have to give it the philosophy of how to apply it,” said Steve West, senior director of network operations control at Southwest Airlines.
“We might have to modify it a little with some human intervention,” he said. “If we can reaccommodate some of our customers and keep everybody else on time, that’s our preference.”
Carriers have also been rolling out new technologies to help travelers cope. Mr. Prest said he used a function on United Airlines’s app to track where his plane was coming from so he would know whether to anticipate a possible delay.
“If it’s looking problematic, you’ve got to expect delays, so you’ve got to know where planes are coming from,” he said.
Last month, American Airlines added notifications that alert travelers if their checked bags have arrived so they are not left waiting at the luggage carousel.
Airlines also say they have become more proactive about offering travelers the opportunity to change their flights without penalty if bad weather is in the forecast.
“We’ve definitely increased the number of waivers we’ve put out this summer compared to other summers,” said Ross Feinstein, a spokesman for American Airlines.
Diana P. Wilson, who lives in Sacramento and works in event logistics, switched a flight for a business trip in Columbus, Ohio, to connect in Denver rather than Chicago after receiving an airline alert that heavy rain was predicted for Chicago.
But Ms. Wilson did not fare much better in Denver, she said, when her flight was delayed because the airline had to find 17 passengers willing to take later flights.
“I started finding out that what was happening was there were weather issues,” Ms. Wilson said. “It was too hot and they had to lighten the plane, and that’s why they needed so many people.”
On Chuck Doherty’s way home to Providence, R.I., from a business trip to Baltimore last month, his flight was delayed nearly three hours because a backup plane was too hot for passengers to board after sitting on the tarmac for much of the day, he said. The backup had been pressed into service because the initial plane was running so far behind schedule.
“They kept telling us they weren’t able to get it cool enough for us to board,” said Mr. Doherty, a software developer. “At one announcement, they said the internal cabin temperature was 110.”
He added, “I fly a lot, and this is absolutely the first time I’ve ever encountered this.”