Guide
Flying in May: when Texas starts to break
US flights ran 78.6% on time in May 2026, still above the annual rate. Dallas Love Field fell to 64.3% as the thunderstorm season arrived in Texas.
Nationally, May 2026 looked like a good month. US domestic flights ran 78.6% on time, above the 77.3% annual rate, and fewer than one in a hundred were cancelled. The Northeast was having one of its best stretches of the year.
Texas was not. Dallas Love Field finished last in the country at 64.3% on time, Houston Hobby ran well below its own annual rate, and Dallas-Fort Worth cancelled more of its schedule than any other big airport. May is the month the southern thunderstorm season arrives.
The national average hides it because the rest of the map is still in its calm spring window.
The first storms, and where they land
US average 78.6%
55.0%90.0%
Source: US DOT Bureau of Transportation Statistics, September 2025 to August 2026.
Apart from San Francisco, the bottom five were all in Texas or Tennessee. Dallas Love Field in May ran 64.3%, Houston Hobby in May 71.9%, Dallas-Fort Worth in May 72.7% and Nashville in May 70.6%. At Dallas-Fort Worth a larger share of its delay minutes than usual was charged to extreme weather: the pattern of severe storms rather than routine congestion.
Convection in Texas and the southern Plains is less frequent than the near-daily storms of the Gulf coast in high summer, but it is more violent. A line of storms over North Texas in late afternoon can close DFW's arrival flow for an hour or more, and at an airport running close to 900 departures a day, an hour is a long queue. The Dallas and Houston guide covers the four Texas airports across the whole year; May is where their seasons diverge from the rest of the country.
San Antonio shows the severe side of the season. San Antonio in May ran a respectable 80.7% on time, yet a larger share of its May delay minutes was charged to extreme weather than at any other big airport that month: fewer storm days than Dallas, but the ones that arrived stopped the operation outright.
The clock matters more than the calendar here, and this is the pattern I would plan around. At Love Field in May 2026, departures in the first window of the day ran above 90% on time; departures between 5pm and 8pm ran under half. The first flight of the morning leaves before the atmosphere has heated enough to build storms. The evening flight inherits every delay of the afternoon, and at Love Field more than half of May's delay minutes were late-arriving aircraft: aircraft that arrived late from somewhere else and passed the delay on.
AprilMay
55.0%85.0%
Figures are on-time percentages. Source: US DOT Bureau of Transportation Statistics, September 2025 to August 2026.
The Plains outside Texas did not follow. Kansas City in May ran 79.5%, Omaha 81.8% and St. Louis 77.5%, all close to their annual rates. Denver slipped too, as its own afternoon storm season began. But in this data May's damage was concentrated in Texas and in the Southwest-heavy airports connected to it, not across the Plains. Next May may draw the line differently, because storm tracks vary from year to year, but the Texas airports' shift from winter to summer was the clearest single pattern in the month.
Southwest carries it
The airports at the bottom share something besides geography. Love Field, Hobby, Nashville and Chicago Midway are all dominated by Southwest, and the airline ran 72.4% on time across its network in May, second-worst of the carriers.
US average 78.6%
60.0%90.0%
Source: US DOT Bureau of Transportation Statistics, September 2025 to August 2026.
Southwest's network is built from short point-to-point legs flown by aircraft that touch several airports a day. When a storm hits Dallas at 3pm, the aircraft stuck there were due in Nashville, Denver and Las Vegas that evening. The airline ran 72.4% network-wide in May but far worse at Love Field itself, as the Southwest at Love Field page shows, and routes from its Texas base show the spread: Dallas Love Field to Denver ran 58.6% on time and Dallas Love Field to Houston Hobby 65.2%, against 74.8% across the year. A hub-and-spoke airline concentrates the damage at its hub; a point-to-point one spreads it across the map.
Republic Airways led the month at 84.4%, with Alaska Airlines and Envoy Air close behind. Spirit was last at 68.4%, and its figure rests on a small schedule: the airline flew very few flights in May 2026, as its airline page shows. Spirit's filings stop in early May 2026, and the data has no Spirit flights at all in June or July, so I would not read its May figure as a verdict on anything.
The rest of the map
The other end of the table belongs to the Northeast and the islands. Kahului (OGG) led at 86.7%, and Newark in May ran 86.4%, its best month of the year, far above its annual 77.4%. Pittsburgh and Cleveland were both in the top ten. The April guide explains why the Northeast does so well between its two bad seasons, and in 2026 that window stayed open through May.
Some of the country's most punctual routes that month ran into Newark: Palm Beach to Newark managed 89.9% against a weak annual 75.8%.
San Francisco was the other outlier, second from bottom at 70.1%. The collapse in arrivals that started in April got worse: Burbank to San Francisco ran 30.9% on time in May. When I first saw figures like that I assumed a bug in my own aggregation; checked against the raw month files, the drop is in the DOT data, and the data does not say why. The Bay Area guide covers the alternatives.
Dallas (DAL)72.6% overall
Dallas-Fort Worth (DFW)72.8% overall
Houston (HOU)76.5% overall
Newark (EWR)77.4% overall
All panels share one scale, 50% to 90% on time. Source: US DOT Bureau of Transportation Statistics, September 2025 to August 2026.
The four panels show the two shapes side by side. The Texas airports peak in winter and fall away from spring into summer. Newark is the mirror image through the spring, then falls away in high summer.
Memorial Day
May's holiday closes the month and opens the summer. In 2026 the weekend ran 74.2% on time, 4.6 points worse than the weeks around it. Atlanta over the 2026 weekend ran far below its normal level, and Dallas-Fort Worth cancelled heavily. The Memorial Day guide covers four years of the weekend in detail.
What I would book in May
Book the first departure out of Texas. At Love Field, Hobby and Dallas-Fort Worth the morning flight ran far better than the evening one in May. The 5am–8am window at Love Field ran 91.5% on time across the year; 8pm–5am ran 53.5%.
Connect somewhere other than Dallas if you can. A May connection through Denver or Atlanta is a better bet than one through DFW in the afternoon. At 72.7% for the month, I would not book an afternoon DFW connection with less than a comfortable buffer. The connection risk tool sets the buffer by hub.
Use May for the Northeast. Newark, Pittsburgh and Cleveland all ran well above their annual rates. By June that ends.
Check the Southwest aircraft's day, not only your flight. An evening Southwest departure anywhere in the network can be carrying a Texas afternoon. The best time to fly tool shows the hour pattern for your route. For what follows in June, see the June guide.
May by airport: Dallas Love Field (DAL) · Dallas-Fort Worth (DFW) · Houston Hobby (HOU) · Nashville (BNA) · Newark (EWR) · Kahului (OGG) · San Francisco (SFO) · Compare any US route