Best Time to Fly STL to PHL: On-Time Stats by Hour & Airline
St Louis Lambert International → Philadelphia International
Data through July 2026 · Last updated October 18, 2026
1,602 flights were scheduled from St. Louis (STL) to Philadelphia (PHL) 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, Republic Airways led with 85.3% on time and Southwest Airlines was last with 75.0%.
Over 24 months, Wednesday was the most reliable day (85% on time) and July the worst month (71%).
The cancellation rate was 1.4% (US average 1.8%).
STL to PHL 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 |
|---|---|---|---|---|
| Republic Airways | 85.3% | 112 min | 1.0% | 96 |
| PSA Airlines | 85.2% | 86 min | 6.6% | 137 |
| American Airlines | 84.2% | 134 min | 1.6% | 644 |
| Southwest Airlines | 75.0% | 58 min | 0.4% | 725 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to PHL
On-time arrival % by scheduled departure hour (local time), 3,198 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 18 | |
| 6am–7am | 88.8% | 2.9% | 650 |
| 7am–8am | 92.3% | 1.8% | 171 |
| 8am–9am | 95.2% | 0.0% | 291 |
| 9am–10am | 87.1% | 3.1% | 128 |
| 10am–11am | 84.5% | 0.0% | 156 |
| 11am–12pm | 88.0% | 0.0% | 83 |
| 12pm–1pm | 75.9% | 0.9% | 109 |
| 1pm–2pm | 78.1% | 1.6% | 381 |
| 2pm–3pm | 78.1% | 3.5% | 285 |
| 3pm–4pm | 65.8% | 2.6% | 39 |
| 4pm–5pm | 63.2% | 2.8% | 176 |
| 5pm–6pm | 67.7% | 4.3% | 140 |
| 6pm–7pm | 76.0% | 0.6% | 168 |
| 7pm–8pm | 70.2% | 0.5% | 200 |
| 8pm–9pm | 69.5% | 1.3% | 154 |
| 9pm–10pm | 55.3% | 4.1% | 49 |
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 PHL
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) | 70.3% | -13.4 pts | 0.0% | 64 |
| Christmas & New Year (Dec 20 - Jan 3) | 73.2% | -10.5 pts | 0.7% | 139 |
| Summer peak (Jun 15 - Aug 15) | 71.8% | -11.9 pts | 3.8% | 609 |
| All other days | 83.7% | — | 1.6% | 2,386 |
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).