Airport month record
DENDEC
Denver International in December 2025
- Departures
- 26,026
- Month
- December 2025
- National, same month
- 73.2%
- Carriers
- 9
Historical statistics for December 2025, not live status or a forecast for this year’s December. For today’s conditions at DEN, see live FAA status.
DEN in December sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, about a point better than the national rate of 73.2%. The late ones land a little over an hour behind schedule. That rests on 26,026 flights, of which United Airlines flew 8,548 at 77.8% on time.
United Airlines is the most reliable of the six carriers covered here at 77.8% on time across 8,548 flights.
Key figures
On time
74.3%
Arrivals under 15 minutes late, of 25,775 completed departures
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.64%
Nationally in December: 1.55%
Whole year
76.6%
DEN across all twelve months
These figures cover 26,026 departures from Denver International in December 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.
Against the year
December next to DEN's other months
Against DEN's own year, December ran 2 points worse than the twelve-month rate of 76.6%, which makes it number nine of twelve months, best first. Either side of it, November ran 84.7% on time and January 82.3%, so a trip moved by a few weeks would have landed in a better stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| September 2025 | 26,548 | 79.4% | 54 min | 0.12% | B+ |
| October 2025 | 27,763 | 80.8% | 52 min | 0.13% | B+ |
| November 2025 | 25,280 | 84.7% | 62 min | 1.44% | B |
| December 2025 (this page) | 26,026 | 74.3% | 68 min | 0.64% | C+ |
| January 2026 | 24,484 | 82.3% | 60 min | 1.69% | B |
| February 2026 | 23,046 | 82.4% | 69 min | 0.88% | B+ |
| March 2026 | 27,089 | 76.8% | 72 min | 1.50% | B |
| April 2026 | 25,345 | 82.5% | 56 min | 0.27% | B+ |
| May 2026 | 27,406 | 76.4% | 58 min | 0.28% | B+ |
| June 2026 | 28,634 | 67.1% | 64 min | 0.41% | C+ |
| July 2026 | 29,503 | 69.6% | 73 min | 0.81% | C+ |
| August 2026 | 28,557 | 67.1% | 80 min | 1.27% | C |
Departure window
The best time of day to leave DEN in December
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 points, against 9 points between the best and worst carrier.
- 5am–8am2,099 flights85.0%
- 8am–11am5,333 flights80.5%
- 11am–2pm5,759 flights74.5%
- 2pm–5pm3,677 flights70.7%
- 5pm–8pm5,641 flights69.7%
- 8pm–5am3,517 flights68.9%
Scale runs 60% to 90%.
Book the early departure. Flights leaving between 5am–8am arrive on time 85.0% of the time, against 68.9% for the overnight window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 5,759 flights scheduled in it.
Across the week, Tuesday is the strongest day at 84.3% on time and Friday the weakest at 63.8%, a spread of 21 points.
Carrier by carrier
Which airlines ran best at DEN in December
The choice of carrier is not cosmetic here. United Airlines arrives on time 77.8% of the time; Southwest Airlines manages 68.4%. Sample sizes sit next to every figure, because a two-point gap across 7,415 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 8,548 | 77.8% | 64 min | 0.22% | B+ |
| Southwest Airlines | 7,415 | 68.4% | 56 min | 0.59% | C+ |
| SkyWest Airlines | 6,240 | 76.7% | 89 min | 0.88% | B+ |
| Frontier Airlines | 1,733 | 75.7% | 63 min | 0.81% | B+ |
| Delta Air Lines | 996 | 73.4% | 80 min | 2.41% | C |
| American Airlines | 723 | 74.1% | 94 min | 0.83% | C+ |
| Alaska Airlinesthin sample | 204 | 63.7% | 53 min | 0.00% | D+ |
| JetBlue Airwaysthin sample | 110 | 72.6% | 153 min | 3.64% | C− |
| Envoy Airthin sample | 39 | 64.1% | 59 min | 0.00% | D+ |
United leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Route by route
Busiest routes out of DEN in December
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DEN to PHX · Phoenix | 775 | 76.1% | 63 min | 0.52% | B+ |
| DEN to LAX · Los Angeles | 651 | 75.2% | 67 min | 0.61% | B+ |
| DEN to SLC · Salt Lake City | 628 | 72.0% | 62 min | 0.32% | C+ |
| DEN to LAS · Las Vegas | 560 | 74.6% | 57 min | 0.36% | C+ |
| DEN to SAN · San Diego | 538 | 70.7% | 59 min | 0.56% | C+ |
| DEN to DFW · Dallas-Fort Worth | 481 | 75.1% | 62 min | 0.00% | B+ |
| DEN to SEA · Seattle | 468 | 59.3% | 63 min | 0.85% | D+ |
| DEN to ATL · Atlanta | 459 | 74.2% | 60 min | 1.09% | C |
| DEN to SFO · San Francisco | 457 | 64.0% | 67 min | 0.22% | D+ |
| DEN to AUS · Austin | 450 | 78.0% | 78 min | 0.00% | B+ |
| DEN to COS · Colorado Springs | 441 | 75.9% | 81 min | 1.13% | B |
| DEN to MSP · Minneapolis | 438 | 68.3% | 67 min | 0.46% | C+ |
| DEN to ORD · Chicago | 416 | 69.4% | 79 min | 0.72% | C+ |
| DEN to MCO · Orlando | 403 | 77.2% | 75 min | 0.50% | B+ |
| DEN to LGA · New York | 391 | 71.4% | 78 min | 4.60% | C− |
| DEN to IAH · Houston | 391 | 82.3% | 56 min | 0.26% | B+ |
| DEN to PDX · Portlandthin sample | 346 | 66.0% | 50 min | 0.29% | C+ |
| DEN to MCI · Kansas Citythin sample | 336 | 77.9% | 67 min | 1.49% | B |
| DEN to SNA · Santa Anathin sample | 316 | 79.2% | 46 min | 0.32% | B+ |
| DEN to IAD · Washingtonthin sample | 307 | 85.2% | 56 min | 0.65% | A+ |
| DEN to SMF · Sacramentothin sample | 303 | 68.6% | 64 min | 0.00% | C+ |
| DEN to BOS · Bostonthin sample | 303 | 85.7% | 58 min | 0.66% | A+ |
| DEN to SAT · San Antoniothin sample | 282 | 76.2% | 49 min | 0.35% | B+ |
| DEN to EWR · Newarkthin sample | 281 | 80.4% | 81 min | 0.36% | B+ |
| DEN to TPA · Tampathin sample | 280 | 79.4% | 84 min | 0.36% | B+ |
Delay causes
What held DEN up in December
Late-arriving aircraft accounts for 44% of the 453,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 34%Carrier
- 17%National Airspace System
- 5%Extreme weather
- 0%Security
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 453,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 453,042 reported delay minutes.
Cancellations are rare at 0.64%, below the national 1.55% 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.
8.8% of arrivals land an hour or more late, close to the national 10.0%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
What to do with this
Flying from DEN in December
For a December trip through DEN: expect 74.3% on time and 0.64% cancelled, going by December 2025. The 5am–8am window was the strongest part of the day.
Related
Where to go next
- Denver International (DEN), the whole year
- DEN in September79.4%
- DEN in October80.8%
- DEN in November84.7%
- DEN in January82.3%
- DEN in February82.4%
- DEN in March76.8%
- DEN in April82.5%
- DEN in May76.4%
- DEN in June67.1%
- DEN in July69.6%
- DEN in August67.1%
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.