Route reliability record
DEN→DAL
Denver to Dallas
- Flights
- 2,999
- Period
- July 2025 to June 2026
- Distance
- 651 mi
- Carriers
- 1
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 2,999 flights, with a median arrival 1 minutes early.
The national on-time rate over the same period is 77.6%, so this route runs 7 points behind the country as a whole. Across a thousand flights that is about 72 extra late arrivals.
Key figures
On time
70.4%
Arrivals under 15 minutes late, of 2,943 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.20%
National rate is 1.81%
Best carrier
Southwest
70.4% on time across 2,999 flights
These figures cover 2,999 flights between July 2025 and June 2026. Beyond the headline rate, 9.2% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on DEN to DAL
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 2,999 | 70.4% | 56 min | 1.20% | C |
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 42 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am496 flights93.0%
- 8am–11am644 flights84.4%
- 11am–2pm528 flights72.6%
- 2pm–5pm477 flights59.1%
- 5pm–8pm598 flights51.4%
- 8pm–5am256 flights51.6%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 51.4% on time, against 93.0% for the 5am–8am 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 8am–11am window is the busiest, with 644 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 31 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 52.1% on time, 31 points below February, the best at 83.5%. 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 289 flights.
Across the week, Wednesday is the strongest day at 75.9% on time and Sunday the weakest at 66.0%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 49,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 48%Late-arriving aircraft
- 30%Carrier
- 20%National Airspace System
- 1%Extreme weather
- 0%Security
48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 49,000 reported delay minutes here, that single category outweighs weather by 34 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 49,183 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.0% on time here.
Cancellations sit at 1.20% against a national 1.81%, which is ordinary. Diversions add another 0.67%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 651 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 69.2% on time across 3,002 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,999 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 83.5% on time and June 52.1%, a swing of 31 points. If the dates move at all, move them out of June before you think about anything else. 2,943 completed flights over 12 months sit behind that.
Common questions
DEN to DAL questions
How often is DEN to DAL delayed?
Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.6% of the 2,999 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is DEN to DAL compared with the rest of the country?
70.4% of flights arrive on time here against a national 77.6%, a difference of 7 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on DEN to DAL?
The 5am–8am departure window is the strongest at 93.0% on time. The 5pm–8pm window is the weakest at 51.4%, 42 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on DEN to DAL?
June is the weakest month at 52.1% on time, compared with 83.5% in February. Across the year that is 31 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DAL to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Dallas Love Field (DAL) delay statistics
- Southwest Airlines on-time record70.4%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. DEN to DAL and DAL to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.