Best Time to Fly SEA to SLC: On-Time Stats by Hour & Airline
Seattle/Tacoma International → Salt Lake City International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 83.6% of Seattle (SEA) to Salt Lake City (SLC) flights arrived on time (4,124 scheduled flights). That is 6.0 points above the national average of 77.6%.
Delta Air Lines was the most punctual of the 4 airlines on the route at 86.8%, while Frontier Airlines trailed at 73.6%.
April has been the best month (89% on time) and Friday the weakest day of the week (82%).
0.8% of flights were cancelled, versus 1.8% nationally.
SEA to SLC on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Delta Air Lines | 86.8% | 58 min | 0.5% | 2,227 |
| Alaska Airlines | 80.1% | 42 min | 1.4% | 1,420 |
| SkyWest Airlines | 80.1% | 47 min | 0.0% | 387 |
| Frontier Airlines | 73.6% | 55 min | 3.3% | 90 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SEA to SLC
On-time arrival % by scheduled departure hour (local time), 8,168 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 94.9% | 0.3% | 730 |
| 6am–7am | 94.3% | 1.1% | 89 |
| 7am–8am | 93.0% | 0.9% | 735 |
| 8am–9am | 92.1% | 1.0% | 193 |
| 9am–10am | 87.6% | 0.6% | 942 |
| 10am–11am | 92.6% | 0.0% | 121 |
| 11am–12pm | 74.5% | 0.7% | 861 |
| 12pm–1pm | 81.2% | 0.0% | 48 |
| 1pm–2pm | 82.7% | 0.4% | 967 |
| 2pm–3pm | 80.3% | 0.7% | 143 |
| 3pm–4pm | 72.5% | 2.4% | 291 |
| 4pm–5pm | 76.7% | 1.5% | 527 |
| 5pm–6pm | 81.0% | 0.1% | 729 |
| 6pm–7pm | 78.7% | 0.8% | 374 |
| 7pm–8pm | 80.9% | 0.1% | 874 |
| 8pm–9pm | 79.7% | 0.3% | 337 |
| 9pm–10pm | 91.8% | 0.5% | 207 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SEA to SLC
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 83.7% | -2.1 pts | 0.0% | 141 |
| Christmas & New Year (Dec 20 - Jan 3) | 81.4% | -4.3 pts | 0.7% | 282 |
| Summer peak (Jun 15 - Aug 15) | 76.1% | -9.6 pts | 0.6% | 1,586 |
| All other days | 85.8% | — | 0.6% | 6,159 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).