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Route Reliability

Seattle → Denver

SEA–DEN · 1,024 miles · Seattle–Tacoma International Airport to Denver International Airport

80
Pretty Reliable
WanderNerd Reliability Score
78%
Arrive within 15 minutes
6 min
Average arrival delay
0.8%
Cancelled
6,325
Flights in the data

Data through May 2026.

Who flies it best

Ranked by on-time arrivals. Historical results, not predictions.

  1. 1.United Airlines87%1,906 flights
  2. 2.Delta Air Lines76%1,089 flights
  3. 3.Alaska Airlines75%1,572 flights
  4. 4.Frontier Airlines75%412 flights
  5. 5.Southwest Airlines71%1,346 flights

What the data says

Morning-you made the right choice.

SEA–DEN flights departing between 3–6 AM arrived on time 98% of the time, versus 65% between 3–6 PM.

Friday is doing you no favors.

SEA–DEN flights arrived on time 83% of the time on Saturdays. On Fridays: 75%.

United Airlines has a clear lead on this route.

United Airlines arrived on time 87% of the time on this route; Southwest Airlines managed 71%.

Best historical flights

Ranked by on-time arrivals, minimum 100 flights. Past performance, not a promise.

Top flights by on-time rate

More flights on this route

The breakdown

On-time by weekday
  • Mon80%(928 flights)
  • Tue77%(830 flights)
  • Wed80%(858 flights)
  • Thu76%(920 flights)
  • Fri75%(915 flights)
  • Sat83%(829 flights)
  • Sun75%(953 flights)
On-time by departure window
  • 3–6 AM98%(632 flights)
  • 6–9 AM85%(1421 flights)
  • 9 AM–12 PM81%(609 flights)
  • 12–3 PM71%(1533 flights)
  • 3–6 PM65%(916 flights)
  • 6–9 PM76%(1120 flights)
  • 9 PM–12 AM—(2 flights)
On-time trend by month
83%
May

Jun 66% → May 83% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202566%629
July 202562%646
August 202567%630
September 202577%572
October 202584%553
November 202586%454
December 202581%461
January 202689%428
February 202686%403
March 202680%443
April 202689%469
May 202683%545

Same trip, other airports

Keep nerding

Based on 6,325 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.