Best Time to Fly SLC to SEA: On-Time Stats by Hour & Airline
Salt Lake City International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
4,125 flights were scheduled from Salt Lake City (SLC) to Seattle (SEA) in the last 12 months, and 80.1% of those that flew arrived on time, 2.5 points above the US average of 77.6%.
Among 4 airlines, Delta Air Lines led with 82.9% on time and Frontier Airlines was last with 67.8%.
Over 24 months, Tuesday was the most reliable day (85% on time) and June the worst month (72%).
The cancellation rate was 0.9% (US average 1.8%).
SLC to SEA 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 | 82.9% | 53 min | 0.5% | 2,230 |
| Alaska Airlines | 77.5% | 47 min | 1.6% | 1,417 |
| SkyWest Airlines | 76.8% | 73 min | 0.0% | 388 |
| Frontier Airlines | 67.8% | 61 min | 3.3% | 90 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SLC to SEA
On-time arrival % by scheduled departure hour (local time), 8,171 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 19 | |
| 6am–7am | 94.6% | 0.5% | 389 |
| 7am–8am | 91.6% | 0.1% | 901 |
| 8am–9am | 93.0% | 0.5% | 405 |
| 9am–10am | 54.9% | 0.2% | 474 |
| 10am–11am | 90.4% | 1.9% | 53 |
| 11am–12pm | 86.8% | 0.7% | 1,174 |
| 12pm–1pm | 81.8% | 0.4% | 226 |
| 1pm–2pm | 84.1% | 1.0% | 621 |
| 2pm–3pm | 85.4% | 2.8% | 106 |
| 3pm–4pm | 74.8% | 0.6% | 1,100 |
| 4pm–5pm | 73.3% | 0.0% | 146 |
| 5pm–6pm | 83.1% | 0.6% | 873 |
| 6pm–7pm | 73.6% | 2.3% | 128 |
| 7pm–8pm | 65.8% | 2.2% | 276 |
| 8pm–9pm | 55.7% | 1.7% | 481 |
| 9pm–10pm | 65.3% | 0.4% | 275 |
| 10pm–11pm | 89.1% | 0.0% | 449 |
| 11pm–12am | 94.7% | 0.0% | 75 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SLC to SEA
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% | +1.0 pts | 0.0% | 141 |
| Christmas & New Year (Dec 20 - Jan 3) | 79.9% | -2.8 pts | 0.4% | 281 |
| Summer peak (Jun 15 - Aug 15) | 70.9% | -11.8 pts | 0.7% | 1,586 |
| All other days | 82.7% | — | 0.7% | 6,163 |
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).