St. Louis (STL) to Philadelphia (PHL): On-Time Performance
Data through July 2026
When you fly STL to PHL matters as much as anything else about the booking: the route swung from 94% on-time in February 2026 to just 66% in July 2025. Across the full period the route averages 80% on-time against a national 78%. Morning departures also hold up better than evening ones (89% vs 69%), which matters most in the rough months.
- On-time
- 80%
- arrived <15 min late
- Avg delay
- 17 min
- completed flights
- Cancelled
- 2.1%
- Flights/day
- 4.4
- last 12 months
- Duration
- 2h 12m
- scheduled
- Distance
- 814 mi
Best airline from STL to PHL
4 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Republic Airwaysmost reliable | 88% | 10 min | 3.2% | 251 |
| PSA Airlines | 82% | 15 min | 5.5% | 365 |
| American Airlines | 80% | 24 min | 2.3% | 1,239 |
| Southwest Airlines | 79% | 13 min | 0.7% | 1,519 |
Monthly on-time trend
Best time to fly from STL to PHL
Aim for departures around 8 a.m. (94% on-time); avoid 9 p.m. departures (53%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 77% | 18 min |
| Tuesday | 81% | 13 min |
| Wednesdaybest | 84% | 14 min |
| Thursday | 82% | 16 min |
| Friday | 77% | 27 min |
| Saturday | 82% | 12 min |
| Sunday | 78% | 19 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft50%
- Airline operations36%
- National airspace system11%
- Weather3%
Frequently asked questions
- How often are flights from STL to PHL delayed?
- 20% of STL–PHL flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 17 minutes.
- Which airline is most reliable from STL to PHL?
- Republic Airways has the best on-time record on this route at 88%, based on 251 flights. 4 airlines flew STL–PHL frequently enough to compare in this period.
- What is the best time of day to fly from STL to PHL?
- Departures around 8 a.m. have the best record (94% on-time), while departures around 9 p.m. have the worst (53%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from STL to PHL?
- The scheduled STL–PHL flight time averages 2h 12m over 814 miles. Actual arrival times vary — flights on this route land 15+ minutes late 20% of the time.
- How often are STL to PHL flights cancelled?
- 2.1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, slightly above the national rate of 1.6%.
- What is the worst month to fly from STL to PHL?
- July 2025 was the roughest month in this dataset, with only 66% of arrivals on time. The best was February 2026 at 94%. If your dates are flexible, that 27-point gap is worth planning around.
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Based on 3,396 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.