Best Time to Fly STL to PIT: On-Time Stats by Hour & Airline
St Louis Lambert International → Pittsburgh International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 79.4% of St. Louis (STL) to Pittsburgh (PIT) flights arrived on time (500 scheduled flights). That is 1.7 points above the national average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
Over 24 months, Tuesday was the most reliable day (87% on time) and May the worst month (67%).
The cancellation rate was 0.0% (US average 1.8%).
STL to PIT 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 |
|---|---|---|---|---|
| Southwest Airlines | 79.4% | 60 min | 0.0% | 500 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to PIT
On-time arrival % by scheduled departure hour (local time), 881 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 7am–8am | Limited data | 10 | |
| 8am–9am | 89.4% | 0.0% | 113 |
| 9am–10am | 87.1% | 0.0% | 62 |
| 10am–11am | 87.9% | 0.0% | 158 |
| 11am–12pm | Limited data | 1 | |
| 12pm–1pm | 85.7% | 0.0% | 35 |
| 1pm–2pm | 83.8% | 0.0% | 68 |
| 2pm–3pm | 85.1% | 1.1% | 88 |
| 3pm–4pm | Limited data | 28 | |
| 4pm–5pm | Limited data | 24 | |
| 5pm–6pm | Limited data | 1 | |
| 6pm–7pm | 80.6% | 0.0% | 139 |
| 7pm–8pm | 61.6% | 0.0% | 99 |
| 8pm–9pm | 36.7% | 3.2% | 31 |
| 9pm–10pm | Limited data | 24 | |
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 PIT
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) | Limited data | 16 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 86.7% | +5.2 pts | 0.0% | 30 |
| Summer peak (Jun 15 - Aug 15) | 76.4% | -5.0 pts | 1.1% | 176 |
| All other days | 81.4% | — | 0.1% | 659 |
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).