Raleigh-Durham airport delays: how reliable is flying out of RDU?

Two flights leave Raleigh-Durham for Washington every few hours, and they cover the same 225-odd miles. Over September 2025 to August 2026, the one to Dulles ran 86.8% on time. The one to Reagan National ran 62.0%, rank 2,949 of 2,978 routes on this site, and cancelled 5.86% of its schedule. Almost everything that goes wrong at RDU follows that pattern.

The airport itself runs well, and the trouble lives at the other end.

Raleigh-Durham International put 78.9% of its 55,470 scheduled departures on time, rank 26 of 60 airports and above the national 77.3%. Its cancellation rate was the weak spot: 2.41% against 1.89% nationally, among the higher rates of the 60 airports. 8.2% of departures arrived an hour or more late, and late flights averaged 81 minutes behind. Figures here cover flights leaving RDU, scored on arrival.

Four big carriers and a large regional layer

RDU has no hub, but it has an unusually even carrier mix. Delta at RDU is the largest operator, followed by American at RDU and Southwest at RDU, with United close behind. Then comes the layer that explains the cancellation rate: Republic Airways at RDU, which flies regional jets under the American, Delta and United brands, runs about one departure in seven.

Delta led the airport in this period. Southwest, American and United clustered around the average. The regionals, Republic and PSA, trailed on punctuality and cancelled far more than the mainline carriers did. Nationally, Republic cancelled 4.55% and PSA 4.80% of their flights, the top two rates among the 14 airlines with pages. Both fly heavily into LaGuardia and Reagan National, where slot limits and tight airspace mean the airline's cheapest answer to a bad afternoon is to cancel a 76-seat regional jet. The regional carriers guide covers who flies what under whose name.

The cause codes point the same way. The air traffic system accounts for 25% of RDU's delay minutes against 21% nationally, a higher share than you would expect from an airfield that rarely has capacity problems of its own. Most of it is inherited from the destination.

Morning is the product

Before 8am, RDU departures ran 90.3% on time. The 5pm to 8pm window ran 67.2%, and flights after 8pm 63.9%, the airport's worst. The morning-to-evening gap of 23.1 points is a little wider than the national 21.3.

Each carrier bends differently. Southwest has the best dawn and one of the worst nights, the pattern of an airline whose aircraft visit several cities before returning in the evening. Delta holds up best late in the day. The first departures are where the airport shines: American 1903 to Charlotte at 6am and Delta 1054 to Boston at 7am rank among the most punctual flight numbers out of RDU, while United 1769, the evening departure to San Francisco, is among the least.

The months: a July, a December, and one bad January

The best month was September 2025 at 84.6%. The worst were July 2026 at 71.9% and December 2025 at 73.5%. July is thunderstorm season along the whole East Coast, and RDU's biggest routes run into the Northeast and Chicago, where summer ground delay programmes pile up in the afternoon.

January 2026 is the month to read on its own page. Its on-time rate, 81.0%, looks healthy, but its cancellation rate was by far the worst of the year, and every major carrier and every big route shared it. That is consistent with winter weather reaching the Triangle itself rather than a storm somewhere down the line: the airport simply stopped for a few days, and the flights that did operate ran cleanly. This year had one such event, and a single year is one sample: another winter could have none, or three. The same month hit RDU's neighbours harder. January 2026 had the highest national cancellation rate of the year, concentrated at Charlotte, Dallas-Fort Worth and Washington National rather than in the snow belt.

Weekday matters less than month here. Tuesday departures ran 81.7% on time and Sunday 75.1%, a 7.3-point spread close to the national 8.1.

The routes: hubs to the west, trouble to the north

The busiest route is also one of the best in the country. RDU to Atlanta ran 86.5%, rank 217 of 2,978, and Delta on that route carries most of it. RDU to Detroit ran 88.6% and RDU to Baltimore 85.8%. RDU to Charlotte, American's 130-mile hop to its hub, ran 81.9%.

The weak routes end at crowded airports in the Northeast and at Chicago. RDU to LaGuardia ran 69.7% and cancelled 6.19%, most of it flown by Republic on the LaGuardia route. RDU to JFK cancelled 5.57%, RDU to Philadelphia 4.16%. RDU to Chicago O'Hare, the second-busiest route, managed only 74.3%.

Then Washington. The Reagan National route is flown almost entirely by regional jets into a slot-controlled field with some of the most restricted airspace in the country; its evening departures are among the least punctual scheduled flying anywhere. The Dulles route, mostly United mainline into an airport with room to spare, is the reverse. The Washington DC airports guide explains why Reagan National behaves this way for everyone.

{
 "flights": 2015,
 "completed": 1893,
 "onTimePct": 62,
 "veryLatePct": 15.2,
 "avgDelayMin": 82.7,
 "medianArrDelay": 3,
 "cancelPct": 5.86,
 "divertPct": 0.2,
 "causes": {
  "carrier": 0.1583,
  "weather": 0.0695,
  "nas": 0.3273,
  "security": 0,
  "lateAircraft": 0.4449
 },
 "byHourBlock": [82.1, 79.4, 64.7, 48.2, 45.8, 39 ],
 "byMonth": [68.4, 59.5, 65.7, 67.7, 65.6, 65.8, 46.9, 62.3, 67.1, 48.6, 62.8, 63.6 ],
 "byDow": [64.5, 61.6, 60.4, 54.1, 55.4, 79.2, 65.9 ]
}

This is the file the pipeline writes for the Reagan National route, trimmed to its headline fields. On this route the cancellation rate, 5.86%, is the line I would read first.

One transcontinental quirk: RDU to San Francisco ran 78.1%, while the return from San Francisco ran 90.1%. The westbound flight lands into San Francisco's arrival flow, and 55% of its delay minutes are coded to the air traffic system; the eastbound one departs from the far less constrained side of the same airport. The opposite-direction guide shows how often San Francisco produces this split.

What I would book from RDU

For Washington, book Dulles. The two routes are the same length and the Dulles one wins by a wide margin on both on-time and cancellation rate. At 62.0% on time, I would not book the Reagan National flight for anything with a fixed start time.

For New York, pick the mainline flight in the morning. If a mainline option exists, prefer it over the regional jet, and fly before 11am. If the trip has a hard deadline, fly the night before: the LaGuardia and JFK routes cancel enough that a same-day rebooking is not guaranteed. The New York airports guide compares the three fields at the far end.

Connect through Atlanta or Charlotte, not O'Hare. Both southern hub routes beat the Chicago one by a wide margin, and a short hop to a hub on the first bank leaves the whole day to recover. The connection risk tool will tell you how much buffer each hub needs.

In winter, watch the forecast for Raleigh itself. RDU's worst cancellations this year came from local winter weather, not from the destination. If ice is forecast for the Triangle, move the trip by a day before the airline does it for you.

Compare the fields: Raleigh-Durham (RDU) · Charlotte (CLT) · Atlanta (ATL) · Washington Dulles (IAD) · Washington National (DCA) · Compare any US route