The sun is shining, there’s not a cloud in the sky, and every other aspect of the summer weather seems picture perfect. Then how come there are so many flight delays?
Heat Makes It Harder to Fly
You would think the icy cold of winter would make it more difficult for airlines to keep things moving, but that’s not always the case. It’s actually harder for planes to fly in hot air because the air itself becomes much less dense. Sparser air molecules means the plane’s wings generate less lift, making takeoff more difficult. Basically, the plane needs to travel greater distances on the runway to reach the speed necessary for getting in the air. Air traffic control will give planes more take-off space to compensate for the heat, and that can back things up on the tarmac considerably. Colder air, on the other hand, is more dense, thus making lift easier to achieve.
If it gets too hot out, airlines will delay or cancel flights altogether until things cool down. Just last week American Airlines grounded 20 flights out of Phoenix Sky Harbor International Airport due to intense heat.
Summer Thunderstorms Affect Routes
Weather is the cause of 69% of all air travel delays, according to the Federal Aviation Administration, but it’s not just blizzards that create all the problems. Weather delays actually peak in May, June, and July, then taper off into the fall. What’s the main culprit? Thunderstorms.
During the summertime, rain and thunderstorms—known as “convective weather”—cause over 40% of all delays affecting airport arrivals (the rest is caused by low ceiling and visibility conditions and wind). Jet aircraft can try to fly over such turbulent areas, but these storms are often the tallest type of obstacle encountered. So, planes usually try to fly around them instead. That changes the flight time, changing the arrival time, which can back up the whole system if the flow is not managed properly. In some cases, thunderstorms can even prevent landing at the right airport, making the situation a lot more complicated for everyone.
More People Fly in the Summer
Summertime is the busiest time in the year for travelers. Everyone is off on vacation, visiting family, or traveling for work. Many flight delays are caused by late arrivals, which are often caused by the high number of passengers on board (when the weather isn’t the culprit). More people flying means longer boarding times, longer unloading times, and more time spent on the tarmac preparing for takeoff.
If you’re worried about getting caught in these summertime delays, try to schedule all your flights in the morning. Milecards points out that even the busiest airports like Newark have about a 90% on-time departure rate before 9 a.m. Compare that to a dismal 55% on-time departure rate after 6 p.m. and the choice is clear. The early morning is cooler, thunderstorms haven’t had time to brew yet, and most of the travelers are business folk who could board a plane in a timely manner with their eyes closed. You probably won’t get any free upgrades, though.