82% of flights from Portland to Denver arrived on time over the past 12 months. That is about the typical U.S. route. The 5 a.m. departures ran on time 96% of the time; the 5 p.m. ones 62%. Most reliable airline: United Airlines (90%). 6% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for PDX → DEN: when a flight was late, it was under 45 minutes late 62% of the time. About 1 in 21 flights landed an hour or more late, and 1 in 204 three hours or more; 0.4% were cancelled outright.
- On time or early82%
- 15–30 min late7.3%
- 30–60 min late5.5%
- 1–2 hours late3.1%
- 2–3 hours late1.1%
- 3+ hours late0.5%
- Diverted0.6%
- Cancelled0.4%
Share of all 4,280 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| United Airlines | 1,820 | 90% | 0.5% | −11 min | 3.3% | +74 min | United Airlines |
| Southwest Airlines | 1,548 | 73% | 0.3% | +1 min | 5.8% | +48 min | Southwest Airlines |
| Alaska Airlines | 656 | 78% | 0.3% | −5 min | 5.8% | +54 min | Alaska Airlines 98%, SkyWest 2% |
| Frontier Airlines | 256 | 81% | 0.4% | −11 min | 5.1% | +52 min | Frontier Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at PDX). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines | Southwest Airlines | Alaska Airlines | Frontier Airlines |
|---|---|---|---|---|
| 5 a.m. | 97% | 94% | — | — |
| 6 a.m. | — | 88% | — | — |
| 7 a.m. | — | 94% | 90% | — |
| 8 a.m. | 96% | 92% | — | — |
| 10 a.m. | — | 69% | — | — |
| noon | 89% | — | — | 85% |
| 1 p.m. | 83% | — | — | — |
| 2 p.m. | — | 55% | 67% | — |
| 4 p.m. | 81% | — | — | — |
| 6 p.m. | 86% | — | — | — |
Last flight of the day
On PDX → DEN, each airline's last flight of the day was cancelled 0.3% of the time, against 0.4% for its earlier flights, so here the last flight is actually the safer one. It arrived 3+ hours late 0.9% of the time (earlier flights: 0.4%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Alaska Airlines | 6:04 p.m. | 0.0% | 0.0% | 0.7% | first flight 7:20 a.m. |
| United Airlines | 6:50 p.m. | 0.3% | 0.8% | 0.5% | first flight 5:00 a.m. |
| Southwest Airlines | 7:40 p.m. | 0.5% | 1.4% | 0.2% | first flight 5:50 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
By month
Each calendar month pooled over 2023–2026. Best: November (89%). Worst: June (74%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 660 | 79% | 0.1% |
| Tuesday | 558 | 82% | 0.2% |
| Wednesday | 578 | 79% | 0.7% |
| Thursday | 652 | 79% | 0.3% |
| Friday | 662 | 82% | 0.8% |
| Saturday | 529 | 84% | 0.4% |
| Sunday | 641 | 86% | 0.2% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: air traffic/airport 7 · weather 5 · airline 4
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| UA 459 | 5:00 a.m. | 362 | 97% | 0.3% | −13 min | United Airlines |
| AS 684 | 7:00 a.m. | 187 | 89% | 0.5% | −10 min | Alaska Airlines |
| UA 2375 | 8:30 a.m. | 365 | 96% | 0.5% | −14 min | United Airlines |
| F9 1790 | 12:20 p.m. | 231 | 82% | 0.0% | −13 min | Frontier Airlines |
| UA 1411 | 12:50 p.m. | 184 | 83% | 0.0% | −11 min | United Airlines |
| AS 1346 | 2:47 p.m. | 126 | 74% | 0.0% | 0 min | Alaska Airlines |
| UA 1787 | 4:15 p.m. | 251 | 82% | 0.0% | −6 min | United Airlines |
| UA 2334 | 6:50 p.m. | 211 | 89% | 0.0% | −20 min | United Airlines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 19, 2025 | 13 | 15% | 1 |
| Feb 17, 2026 | 9 | 22% | 0 |
| Jun 24, 2026 | 15 | 33% | 0 |
| Aug 15, 2026 | 12 | 33% | 0 |
| Aug 22, 2026 | 12 | 33% | 1 |
Questions
How often are flights from PDX to DEN on time?
82% of 4,280 scheduled flights from Portland, OR to Denver, CO arrived within 15 minutes of schedule between September 2025 and August 2026. 0.4% were cancelled.
What is the best time of day to fly PDX to DEN?
Flights scheduled to leave at 5 a.m. were the most reliable (96% on time). The 5 p.m. departures were the least (62%).
Which airline is most on time from PDX to DEN?
United Airlines: 90% of its 1,820 flights on the route arrived on time. Southwest Airlines: 73%. Alaska Airlines: 78%. Frontier Airlines: 81%.
What month has the most delays from PDX to DEN?
June (74% on time). The best month is November (89%), over 2023–2026.
Is the last flight of the day from PDX to DEN more likely to be cancelled?
No, the opposite. Each airline's last PDX–DEN flight of the day was cancelled 0.3% of the time over the past year, against 0.4% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- DEN → PDX (return)
- Portland (PDX) delays by hour
- Flights into Denver (DEN)
- United Airlines on-time record
- Southwest Airlines on-time record
- Alaska Airlines on-time record
- Frontier Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.