SEA to DEN flight delays & on-time performance
Nonstop flights from Seattle–Tacoma International Airport to Denver International Airport · 1,024 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SEA or DEN right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Seattle (SEA) to Denver (DEN) arrived on time 78% of the time in Aug 2025 – Jul 2026, in line with the national average.
- 0.7% were cancelled, and 6% arrived an hour or more late.
- United Airlines was the most punctual airline here (88% on time); Southwest Airlines was the least (68%).
- Departures scheduled around 5am did best (97% on time); around 2pm did worst (60%).
- Saturday was the most reliable day to fly (83% on time) and Sunday the least (76%).
- The largest source of delay minutes was late-arriving aircraft (37%).
Which airline is most on time from SEA to DEN?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| United Airlines | 88% | 0.7% | 9 min | 4.3% | 1,908 |
| SkyWest AirlinesRegional airline operating flights for United Express, Delta Connection, American Eagle and Alaska. | 85% | 0.5% | 10 min | 5.5% | 221 |
| Alaska Airlines | 78% | 0.7% | 12 min | 5.3% | 1,551 |
| Frontier Airlines | 77% | 1.4% | 15 min | 8.2% | 431 |
| Delta Air Lines | 73% | 0.9% | 17 min | 8.3% | 869 |
| Southwest Airlines | 68% | 0.6% | 17 min | 7.2% | 1,345 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am97%655 flights
- 6am91%124 flights
- 7am84%355 flights
- 8am86%888 flights
- 9am91%161 flights
- 10am79%153 flights
- 11am79%309 flights
- 12pm78%624 flights
- 1pm68%576 flights
- 2pm60%420 flights
- 3pm76%600 flights
- 4pm51%189 flights
- 5pm70%101 flights
- 6pm77%183 flights
- 7pm76%706 flights
- 8pm76%279 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday78%0.8% cancelled
- Tuesday79%0.5% cancelled
- Wednesday80%0.2% cancelled
- Thursday78%1.1% cancelled
- Friday76%1.3% cancelled
- Saturday83%0.5% cancelled
- Sunday76%0.7% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft37%
- Airline (crew, maintenance, cleaning, fueling)31%
- Air traffic control & airport congestion27%
- Extreme weather4%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Airline (crew, maintenance, cleaning, fueling)53%
- Air traffic control & airport congestion28%
- Extreme weather19%
- Security0%
SEA to DEN: common questions
- How often are SEA to DEN flights on time?
- 78% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Seattle to Denver cancelled?
- 0.7% of scheduled flights were cancelled (47 of 6,325).
- How long are typical delays?
- Across all flights the average arrival delay was 13 min (early arrivals count as zero). Flights that were late arrived 55 min behind schedule on average, and 6.0% of flights were an hour or more late.
- How long is taxi time at SEA?
- Flights on this route spent 21 min taxiing from the gate to takeoff on average.
Related routes
Return trip: DEN to SEA — 75% on time
More flights from Seattle
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SEA → DEN, nonstop flights by US airlines that report to the DOT. How we calculate this.