Carrier route record
WNDEN→RDU
Southwest Airlines · Denver to Raleigh
- Flights
- 709
- Period
- September 2025 to August 2026
- Share of route
- 41%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to RDU draws a D+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 50 minutes behind schedule. Build slack into anything you connect to. That rests on 709 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.3%, so Southwest on DEN to RDU runs 13 points behind the country as a whole. Across a thousand flights that is about 125 extra late arrivals.
Key figures
On time
64.8%
Arrivals under 15 minutes late, of 702 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.89%
Whole route
76.0%
Every carrier on DEN to RDU, 1,732 flights
These figures cover 709 flights between September 2025 and August 2026. Beyond the headline rate, 9.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on DEN to RDU
Southwest flew 709 of the 1,732 flights on DEN to RDU, about 41% of it. Its 64.8% on time is 11 points worse than the route as a whole, which runs 76.0%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Frontier at 87.4% to Southwest at 64.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 296 | 87.4% | 56 min | 1.01% | A |
| United Airlines | 727 | 82.3% | 66 min | 0.41% | B+ |
| Southwest Airlines (this page) | 709 | 64.8% | 52 min | 0.85% | D+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against half a point between the best and worst carrier.
- 5am–8am8 flights—
- 8am–11am246 flights77.0%
- 11am–2pm103 flights71.6%
- 2pm–5pm41 flights77.5%
- 5pm–8pm279 flights50.2%
- 8pm–5am32 flights59.4%
Scale runs 40% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 50.2% on time, against 77.5% for the 2pm–5pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 279 flights scheduled in it.
Across the year
Southwest on DEN to RDU through the year
June is the worst month at 46.9% on time, 40 points below January, the best at 87.3%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 65 flights.
Across the week, Wednesday is the strongest day at 72.8% on time and Thursday the weakest at 57.3%, a spread of 16 points.
Arrival by arrival
How late Southwest on DEN to RDU runs when it is late
The 247 late arrivals split 101 under half an hour, 80 between 30 and 60 minutes, and 66 an hour or more.
- 15+ min early73 flights10.4%
- Within 15 min382 flights54.4%
- 15–29 min late101 flights14.4%
- 30–59 min late80 flights11.4%
- 1–2 hours late42 flights6.0%
- 2+ hours late24 flights3.4%
Scale runs 0% to 100%.
Share of 702 completed flights by arrival against schedule.
74 of 287 late departures made up the time and arrived on time, 26% of them. 34 flights left on time and still arrived late.
The worst days
Worst days for Southwest on DEN to RDU
The latest arrival of the period was on 13 August 2026, 4 hours 29 minutes behind schedule; most of its delay minutes were filed as extreme weather. Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 August 2026 | 4 hours 29 minutes | Extreme weather |
| 9 July 2026 | 4 hours 10 minutes | Late-arriving aircraft |
| 21 August 2026 | 3 hours 55 minutes | Late-arriving aircraft |
| 3 August 2026 | 3 hours 53 minutes | Carrier |
| 19 December 2025 | 3 hours 32 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 56% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 56%Late-arriving aircraft
- 30%Carrier
- 11%National Airspace System
- 3%Extreme weather
56% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 13,000 reported delay minutes here, that single category outweighs weather by 22 to one. The split is drawn from 12,899 reported delay minutes.
Cancellations are rare at 0.85%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
9.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 1,436 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 74.8% on time across 710 flights, 10 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.
One caution: this is a thin sample. 709 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DEN to RDU
Put together: treat all of this as provisional. 709 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 64.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 702 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to RDU, every carrier
- Southwest on RDU to DEN, the return leg
- Frontier Airlines on DEN to RDU87.4%
- United Airlines on DEN to RDU82.3%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Raleigh-Durham International (RDU) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.