Best Time to Fly STL to ATL: On-Time Stats by Hour & Airline
St Louis Lambert International → Hartsfield-Jackson Atlanta International
Data through July 2026 · Last updated October 18, 2026
3,684 flights were scheduled from St. Louis (STL) to Atlanta (ATL) in the last 12 months, and 84.9% of those that flew arrived on time, 7.2 points above the US average of 77.6%.
Among 3 airlines, Delta Air Lines led with 89.4% on time and Frontier Airlines was last with 59.9%.
Over 24 months, Wednesday was the most reliable day (91% on time) and July the worst month (79%).
The cancellation rate was 1.7% (US average 1.8%).
STL to ATL 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 | 89.4% | 79 min | 2.0% | 2,357 |
| Southwest Airlines | 80.3% | 56 min | 1.1% | 1,105 |
| Frontier Airlines | 59.9% | 96 min | 1.8% | 222 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to ATL
On-time arrival % by scheduled departure hour (local time), 7,192 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 27 | |
| 6am–7am | 92.1% | 1.5% | 745 |
| 7am–8am | 94.5% | 1.2% | 1,006 |
| 8am–9am | 95.5% | 1.0% | 200 |
| 9am–10am | 93.7% | 2.2% | 404 |
| 10am–11am | 91.1% | 0.8% | 708 |
| 11am–12pm | 85.6% | 1.3% | 303 |
| 12pm–1pm | 88.5% | 0.8% | 361 |
| 1pm–2pm | 83.2% | 0.8% | 505 |
| 2pm–3pm | 83.8% | 4.2% | 168 |
| 3pm–4pm | 81.9% | 1.2% | 519 |
| 4pm–5pm | 73.4% | 0.9% | 433 |
| 5pm–6pm | 79.5% | 1.3% | 753 |
| 6pm–7pm | 78.5% | 2.6% | 416 |
| 7pm–8pm | 70.7% | 1.4% | 416 |
| 8pm–9pm | 68.1% | 0.5% | 190 |
| 9pm–10pm | 68.4% | 0.0% | 38 |
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 ATL
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) | 74.6% | -11.8 pts | 0.7% | 136 |
| Christmas & New Year (Dec 20 - Jan 3) | 84.0% | -2.4 pts | 0.7% | 303 |
| Summer peak (Jun 15 - Aug 15) | 82.3% | -4.1 pts | 1.3% | 1,351 |
| All other days | 86.4% | — | 1.4% | 5,402 |
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).