77% of flights from St. Louis to Philadelphia arrived on time over the past 12 months. That is about the typical U.S. route. The 8 a.m. departures ran on time 97% of the time; the 5 p.m. ones 64%. Most reliable airline: American Airlines (81%). 11% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for STL → PHL: when a flight was late, it was under 45 minutes late 48% of the time. About 1 in 12 flights landed an hour or more late, and 1 in 45 three hours or more; 1.8% were cancelled outright.
- On time or early77%
- 15–30 min late6.7%
- 30–60 min late5.7%
- 1–2 hours late5.2%
- 2–3 hours late1.1%
- 3+ hours late2.2%
- Diverted0.2%
- Cancelled1.8%
Share of all 1,606 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| American Airlines | 881 | 81% | 2.9% | −15 min | 8.9% | +130 min | American Airlines 71%, PSA Airlines 18%, Republic Airways 11% |
| Southwest Airlines | 725 | 72% | 0.4% | 0 min | 8.3% | +58 min | Southwest Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at STL). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | American Airlines | Southwest Airlines |
|---|---|---|
| 6 a.m. | 88% | — |
| 8 a.m. | — | 97% |
| 10 a.m. | — | 85% |
| 11 a.m. | 75% | — |
| 5 p.m. | 65% | — |
Last flight of the day
On STL → PHL, each airline's last flight of the day was cancelled 2.2% of the time, against 1.4% for its earlier flights (1.6× as often). It arrived 3+ hours late 3.2% of the time (earlier flights: 1.8%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| American Airlines | 5:42 p.m. | 3.9% | 3.3% | 2.3% | first flight 6:14 a.m. |
| Southwest Airlines | 7:10 p.m. | 0.0% | 3.0% | 0.0% | first flight 10:20 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in PHL tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: April (85%). Worst: July (67%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 250 | 74% | 3.2% |
| Tuesday | 229 | 79% | 0.9% |
| Wednesday | 227 | 83% | 0.9% |
| Thursday | 237 | 78% | 1.3% |
| Friday | 240 | 78% | 1.3% |
| Saturday | 177 | 77% | 1.1% |
| Sunday | 246 | 72% | 3.7% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 24 · airline 3 · air traffic/airport 2
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| AA 1308 | 6:00 a.m. | 175 | 90% | 0.6% | −17 min | American Airlines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Nov 10, 2025 | 5 | 0% | 1 |
| Oct 18, 2025 | 4 | 0% | 0 |
| Feb 23, 2026 | 3 | 0% | 3 |
| Jan 25, 2026 | 3 | 0% | 3 |
| Apr 27, 2026 | 5 | 20% | 0 |
Questions
How often are flights from STL to PHL on time?
77% of 1,606 scheduled flights from St. Louis, MO to Philadelphia, PA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.8% were cancelled.
What is the best time of day to fly STL to PHL?
Flights scheduled to leave at 8 a.m. were the most reliable (97% on time). The 5 p.m. departures were the least (64%).
Which airline is most on time from STL to PHL?
American Airlines: 81% of its 881 flights on the route arrived on time. Southwest Airlines: 72%.
What month has the most delays from STL to PHL?
July (67% on time). The best month is April (85%), over 2023–2026.
Is the last flight of the day from STL to PHL more likely to be cancelled?
Yes. Each airline's last STL–PHL flight of the day was cancelled 2.2% of the time over the past year, against 1.4% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- PHL → STL (return)
- St. Louis Lambert (STL) delays by hour
- Flights into Philadelphia (PHL)
- American Airlines on-time record
- Southwest Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.