Best Time to Fly STL to SLC: On-Time Stats by Hour & Airline
St Louis Lambert International → Salt Lake City International
Data through July 2026 · Last updated October 18, 2026
990 flights were scheduled from St. Louis (STL) to Salt Lake City (SLC) in the last 12 months, and 87.3% of those that flew arrived on time, 9.7 points above the US average of 77.6%.
Delta Air Lines was the only reporting airline with regular flights on this route.
September has been the best month (93% on time) and Saturday the weakest day of the week (87%).
0.9% of flights were cancelled, versus 1.8% nationally.
STL 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 | 87.5% | 104 min | 0.9% | 979 |
| SkyWest Airlines | Limited data | 2 | ||
| Southwest Airlines | Limited data | 9 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to SLC
On-time arrival % by scheduled departure hour (local time), 1,951 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 86.4% | 0.0% | 103 |
| 7am–8am | 93.7% | 0.5% | 572 |
| 8am–9am | 94.4% | 1.8% | 55 |
| 1pm–2pm | Limited data | 9 | |
| 2pm–3pm | 87.7% | 0.7% | 543 |
| 4pm–5pm | Limited data | 10 | |
| 5pm–6pm | 94.0% | 0.6% | 170 |
| 6pm–7pm | 88.3% | 0.5% | 206 |
| 7pm–8pm | 81.7% | 1.5% | 267 |
| 8pm–9pm | Limited data | 16 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on STL 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) | 80.6% | -9.7 pts | 0.0% | 36 |
| Christmas & New Year (Dec 20 - Jan 3) | 84.8% | -5.5 pts | 1.7% | 60 |
| Summer peak (Jun 15 - Aug 15) | 87.4% | -2.8 pts | 0.8% | 369 |
| All other days | 90.2% | — | 0.7% | 1,486 |
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).