Carrier performance at one airport
DL→DEN
Delta Air Lines at Denver International
- Departures
- 11,579
- Period
- July 2025 to June 2026
- Routes
- 9
- Rank here
- #1 of 9
Delta Air Lines at Denver lands a B, 6 points better than the national rate of 77.6%. About one flight in six arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 11,579 flights, of which Delta Air Lines flew 11,579 at 83.1% on time.
Measured against the airport rather than the country, Delta Air Lines runs 7 points ahead of the 76.3% weighted average across all carriers at DEN. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
83.1%
11,392 completed departures
Avg delay
77 min
Across delayed flights only
Cancelled
1.33%
At DEN, this carrier only
Rank here
#1
Of 9 carriers clearing the floor at DEN
These figures cover 12,000 flights between July 2025 and June 2026. The median arrival is 10 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Against the competition
Every carrier at DEN, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 83.1% of the time; JetBlue Airways manages 68.9%. Sample sizes sit next to every figure, because a two-point gap across 1,249 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 11,579 | 83.1% | 77 min | 1.33% | B |
| SkyWest Airlines | 75,349 | 80.0% | 77 min | 1.13% | B |
| United Airlines | 107,305 | 78.4% | 64 min | 0.46% | B+ |
| Frontier Airlines | 22,581 | 78.0% | 67 min | 0.73% | B+ |
| American Airlines | 8,874 | 76.8% | 104 min | 2.12% | B |
| Alaska Airlines | 2,700 | 76.0% | 56 min | 0.89% | B+ |
| Allegiant Air | 395 | 70.3% | 110 min | 1.27% | C |
| Southwest Airlines | 88,768 | 69.4% | 54 min | 0.70% | C+ |
| JetBlue Airways | 1,249 | 68.9% | 89 min | 2.80% | C |
The spread between Delta and JetBlue is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.
Route by route
Where Delta Air Lines flies from DEN
Delta Air Lines operates 9 routes out of DEN with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DEN to ATL · Atlanta | 2,805 | 86.3% | 71 min | 1.07% | A |
| DEN to MSP · Minneapolis | 1,805 | 81.1% | 73 min | 0.89% | B+ |
| DEN to SLC · Salt Lake City | 1,689 | 82.3% | 81 min | 0.41% | B+ |
| DEN to DTW · Detroit | 1,252 | 86.2% | 75 min | 0.48% | A+ |
| DEN to LGA · New York | 1,036 | 79.0% | 81 min | 4.44% | B− |
| DEN to JFK · New York | 978 | 87.0% | 80 min | 2.45% | A |
| DEN to SEA · Seattle | 868 | 79.2% | 89 min | 0.92% | B+ |
| DEN to LAX · Los Angeles | 746 | 80.5% | 89 min | 1.47% | B |
| DEN to BOS · Boston | 400 | 75.8% | 56 min | 1.50% | B |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,340 flights89.9%
- 8am–11am1,149 flights85.0%
- 11am–2pm2,883 flights80.5%
- 2pm–5pm2,054 flights83.2%
- 5pm–8pm1,449 flights67.7%
- 8pm–5am704 flights88.6%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.9% of the time, against 67.7% for the evening window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 3,340 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 72.6% on time, 17 points below April, the best at 89.8%. 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 1,119 flights.
Delay causes
What holds this operation up
- 42%Late-arriving aircraft
- 40%Carrier
- 14%National Airspace System
- 3%Extreme weather
- 0%Security
42% 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 148,000 reported delay minutes here, that single category outweighs weather by 12 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 148,393 reported delay minutes.
Cancellations sit at 1.33% against a national 1.81%, which is ordinary. Diversions add another 0.28%.
6.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.
The sample behind these figures is 11,579 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 89.8% on time and July 72.6%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 11,392 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at DEN
How often is Delta Air Lines at DEN delayed?
About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.9% of the 11,579 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on Delta Air Lines at DEN?
Delta Air Lines leads at 83.1% on time across 11,579 flights. JetBlue Airways is at the other end on 68.9%, a gap of 14 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Delta Air Lines at DEN?
The 5am–8am departure window is the strongest at 89.9% on time. The 5pm–8pm window is the weakest at 67.7%, 22 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 July delays on Delta Air Lines at DEN?
July is the weakest month at 72.6% on time, compared with 89.8% in April. Across the year that is 17 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
- Delta Air Lines network-wide record
- Denver International (DEN) all carriers
- DEN to ATL route record86.3%
- DEN to MSP route record81.1%
- DEN to SLC route record82.3%
- DEN to DTW route record86.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.