Best Time to Fly ONT to SLC: On-Time Stats by Hour & Airline
Ontario International → Salt Lake City International
Data through July 2026 · Last updated October 18, 2026
1,239 flights were scheduled from Ontario (ONT) to Salt Lake City (SLC) in the last 12 months, and 91.6% of those that flew arrived on time, 14.0 points above the US average of 77.6%.
Delta Air Lines was the most punctual of the 3 airlines on the route at 92.0%, while Frontier Airlines trailed at 86.7%.
October has been the best month (96% on time) and Thursday the weakest day of the week (90%).
0.9% of flights were cancelled, versus 1.8% nationally.
ONT 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 | 92.0% | 82 min | 1.1% | 899 |
| SkyWest Airlines | 90.9% | 100 min | 0.3% | 310 |
| Frontier Airlines | 86.7% | 42 min | 0.0% | 30 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ONT to SLC
On-time arrival % by scheduled departure hour (local time), 2,426 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 18 | |
| 6am–7am | 94.8% | 0.3% | 712 |
| 7am–8am | Limited data | 2 | |
| 8am–9am | Limited data | 11 | |
| 9am–10am | 97.4% | 1.0% | 192 |
| 10am–11am | 93.5% | 0.0% | 31 |
| 11am–12pm | Limited data | 6 | |
| 1pm–2pm | 88.8% | 0.5% | 738 |
| 3pm–4pm | Limited data | 6 | |
| 4pm–5pm | 92.9% | 0.5% | 197 |
| 5pm–6pm | 93.8% | 0.6% | 499 |
| 6pm–7pm | Limited data | 14 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on ONT 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) | 95.0% | +2.0 pts | 0.0% | 40 |
| Christmas & New Year (Dec 20 - Jan 3) | 88.2% | -4.7 pts | 1.2% | 86 |
| Summer peak (Jun 15 - Aug 15) | 91.8% | -1.1 pts | 0.4% | 467 |
| All other days | 93.0% | — | 0.6% | 1,833 |
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).