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Route Reliability

Salt Lake City → Seattle

SLC–SEA · 689 miles · Salt Lake City International Airport to Seattle–Tacoma International Airport

84
Pretty Reliable
WanderNerd Reliability Score
80%
Arrive within 15 minutes
2 min
Average arrival delay
1.0%
Cancelled
4,148
Flights in the data

Data through May 2026.

Who flies it best

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

  1. 1.Delta Air Lines84%2,222 flights
  2. 2.Alaska Airlines76%1,819 flights
  3. 3.Frontier Airlines70%107 flights

What the data says

Morning flights do better here.

SLC–SEA flights departing between 6–9 AM arrived on time 93% of the time, versus 68% between 6–9 PM.

Tuesday comes out ahead.

A small edge: 83% on time on Tuesdays against 77% on Fridays.

Delta Air Lines runs this route best.

Delta Air Lines arrived on time 84% of the time on this route; Frontier Airlines managed 70%.

Ticking up lately.

SLC–SEA flights arrived on time 86% of the time over the last three months in the data, compared with 82% in the three months before that.

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%(648 flights)
  • Tue83%(543 flights)
  • Wed81%(538 flights)
  • Thu79%(605 flights)
  • Fri77%(629 flights)
  • Sat82%(509 flights)
  • Sun78%(630 flights)
On-time by departure window
  • 3–6 AM90%(19 flights)
  • 6–9 AM93%(739 flights)
  • 9 AM–12 PM78%(845 flights)
  • 12–3 PM83%(573 flights)
  • 3–6 PM77%(1061 flights)
  • 6–9 PM68%(479 flights)
  • 9 PM–12 AM80%(386 flights)
On-time trend by month
84%
May

Jun 68% → May 84% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202568%375
July 202574%390
August 202573%404
September 202583%396
October 202581%362
November 202584%289
December 202572%300
January 202685%298
February 202687%292
March 202686%324
April 202689%323
May 202684%349

Keep nerding

Based on 4,148 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.