Historical on-time performance
Seattle to Salt Lake City
689 miData through May 2026Source: US DOT · BTS
Flights on SEA–SLC arrive on time 82% of the time over the last 12 months.
On-time rate82%arrived within 15 min
p90 delay25 min1 in 10 flights is worse (tail risk)
Cancelled0.9%of scheduled flights
based on 3,992 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Delta Air LinesbestOn-time86%Medianon timep9020 minCancel0.6%Flights2,218
- SkyWest AirlinesOn-time80%Medianon timep9030 minCancel0.0%Flights419
- Alaska AirlinesOn-time77%Medianon timep9030 minCancel1.8%Flights1,355
Why flights run late
Delay causes
- Airline50%
- Weather2%
- Air traffic (NAS)11%
- Late aircraft38%
- Security0%
Most delay minutes here are attributed to Airline.
When flights don't go
Why flights were cancelled
- Airline57%
- Weather27%
- Air traffic (NAS)16%
- Security0%
Most cancellations here are attributed to Airline. Shares are among 37 cancellations with a reported cause (BTS reports causes from June 2003).
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly SEA → SLC
All airlines · rolling 36 months (2023-06 .. 2026-05).
Best time of day
Mornings are the most reliable time of day to fly this route — 90% on time.
- Mornings90% on time · p90 10 min · 3,896 flights
- Overnights83% on time · p90 25 min · 683 flights
- Middays81% on time · p90 25 min · 3,012 flights
- Evenings80% on time · p90 30 min · 3,097 flights
- Afternoons74% on time · p90 40 min · 1,221 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 80% to 86% on time.
- Wednesdays86% on time · p90 20 min · 1,605 flights
- Tuesdays85% on time · p90 20 min · 1,602 flights
- Saturdays83% on time · p90 20 min · 1,522 flights
- Mondays83% on time · p90 25 min · 1,816 flights
- Thursdays82% on time · p90 25 min · 1,783 flights
- Sundays81% on time · p90 25 min · 1,761 flights
- Fridays80% on time · p90 30 min · 1,820 flights
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