Route profile
STL→ATL
Flight reliability, delays and best times to fly from St. Louis to Atlanta, 484 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 85% of comparable major US routes (4,598 compared)
Calculated from 11,039 flights. How this is calculated
STL → ATL arrives on time 85.0% of the time; the return trip, ATL → STL, arrives on time 81.7% of the time, a 3.4-point gap between the two directions of the same city pair.
STL → ATL spends 20.3 minutes on the ground on a 484-mile trip: 11.5 minutes from pushback to wheels-up at STL and 8.8 minutes from touchdown to gate at ATL.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
The airline matters unusually much on this route, a wider carrier-to-carrier gap than 99% of 2,692 comparable routes.
Delta Air Lines arrived on time 88.4% of the time, against 60.3% for Frontier Airlines, flying the exact same route.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 2,692 in the comparison.
Why STL → ATL flights are cancelled
July 2023 – July 2026
STL → ATL cancelled 119 of 11,039 scheduled flights — about 1 in every 93. The reason filed most often was the airline, 55.5% of the cancellations coded on this route — about 1 in every 167 scheduled flights.
Share of cancellations
Of 119 cancelled departures carrying a reason code.
What each reason means
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
66 cancellations, 55.5% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
51 cancellations, 42.9% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
2 cancellations, 1.7% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
119 coded cancellations were recorded on STL → ATL; the section appears from 50.
When it goes wrong
July 2023 – July 2026
27 min late
against a median of 10 min early
Percentiles over 11,039 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at ATL after arriving from STL.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 27% | High risk |
| 45 min | 15% | Some risk |
| 60 min | 9.1% | Some risk |
| 90 min | 4.7% | Low risk |
| 120 min | 2.9% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.08% of the time and diverts 0.24% of the time, which a late arrival never shows up in.
Chance of missing is the share of 10,894 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 27 minutes late (90th-percentile gate arrival delay), over 11,039 operations.
Any other layover length: connection checker.
Best time to fly
STL → ATL flights departing 5–9 AM arrived on time 93.0% of the time, against 74.2% for 6–9 PM departures, a gap of 18.8 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 94.6% on time from 129 flights
- 6 AM: 91.1% on time from 1,201 flights
- 7 AM: 94.2% on time from 1,487 flights
- 8 AM: 94.1% on time from 357 flights
- 9 AM: 91.6% on time from 548 flights
- 10 AM: 91.0% on time from 1,058 flights
- 11 AM: 84.9% on time from 422 flights
- 12 PM: 86.3% on time from 512 flights
- 1 PM: 84.4% on time from 806 flights
- 2 PM: 82.7% on time from 307 flights
- 3 PM: 81.5% on time from 765 flights
- 4 PM: 73.5% on time from 651 flights
- 5 PM: 79.6% on time from 1,151 flights
- 6 PM: 77.8% on time from 588 flights
- 7 PM: 73.8% on time from 667 flights
- 8 PM: 68.5% on time from 330 flights
- 9 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why STL → ATL runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for STL → ATL. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on STL → ATL, at 45.4%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 93.0% of the time and 6–9 PM departures 74.2%.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of STL to ATL: 3.7 times the normal rate at STL and 3.3 times at ATL. Cancelled in bad weather against normal hours: STL 3.5% against 0.9%, ATL 3.4% against 1.0%. Flights that did leave ATL in bad weather arrived on time 66.5% of the time, against 80.2% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | STL | ATL |
|---|---|---|
| Cancelled in bad weather | 3.5% | 3.4% |
| Cancelled in normal hours | 0.9% | 1.0% |
| Arrived on time, bad weather | 67.0% | 66.5% |
| Arrived on time, normal hours | 80.4% | 80.2% |
| Departures in bad weather | 18,612 | 105,854 |
Delta Air Lines (1.6% cancelled against 3.6% for the other carriers at STL) and Southwest Airlines (3.2% cancelled against 4.3% for the other carriers at STL) cancelled fewer departures from STL in bad weather than the other carriers there did in the same months. None of the route’s other carriers was clearly worse. One more carrier flies this route but has too few bad-weather departures from STL to compare.
This route’s airlines in bad weather at STL
All departures from STL| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| Delta Air Lines | 1,563 | 1.6%below the others | 3.6% |
| Southwest Airlines | 11,665 | 3.2%below the others | 4.3% |
These are airport figures, not route figures: every scheduled departure from STL and ATL, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from STL on every route.
Weather source and limits. In full: STL (airlines), ATL, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 6,975 | 88.4% | 1.18% | -12 min | 4.1% |
| Southwest Airlines | 3,820 | 80.4% | 0.86% | -5 min | 5.4% |
| Frontier Airlines | 244 | 60.3% | 1.64% | 4 min | 17.2% |
Delta Air Lines flew 63.2% of the 11,039 flights listed.
Delta Air Lines arrived on time 28.1 percentage points more often than Frontier Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 8.5 percentage points.
By month
- Jan: 85.4%
- Feb: 87.3%
- Mar: 83.8%
- Apr: 86.8%
- May: 80.3%
- Jun: 83.0%
- Jul: 75.5%
- Aug: 86.6%
- Sep: 91.8%
- Oct: 91.8%
- Nov: 89.6%
- Dec: 83.0%
July is historically the weakest month and September the strongest, a spread of 16.3 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 76.2% from 305 flights
- August 2023: 82.5% from 311 flights
- September 2023: 92.2% from 294 flights
- October 2023: 90.9% from 298 flights
- November 2023: 93.0% from 316 flights
- December 2023: 85.9% from 321 flights
- January 2024: 79.9% from 264 flights
- February 2024: 88.7% from 248 flights
- March 2024: 86.5% from 290 flights
- April 2024: 88.8% from 295 flights
- May 2024: 79.5% from 313 flights
- June 2024: 87.4% from 294 flights
- July 2024: 66.4% from 298 flights
- August 2024: 90.2% from 299 flights
- September 2024: 88.0% from 285 flights
- October 2024: 94.5% from 294 flights
- November 2024: 90.9% from 276 flights
- December 2024: 82.2% from 292 flights
- January 2025: 88.2% from 264 flights
- February 2025: 84.1% from 247 flights
- March 2025: 86.1% from 282 flights
- April 2025: 85.4% from 285 flights
- May 2025: 79.7% from 302 flights
- June 2025: 80.2% from 331 flights
- July 2025: 81.3% from 351 flights
- August 2025: 87.1% from 331 flights
- September 2025: 95.0% from 317 flights
- October 2025: 90.2% from 348 flights
- November 2025: 84.2% from 284 flights
- December 2025: 80.7% from 311 flights
- January 2026: 88.1% from 279 flights
- February 2026: 88.9% from 254 flights
- March 2026: 78.5% from 283 flights
- April 2026: 86.0% from 299 flights
- May 2026: 81.5% from 330 flights
- June 2026: 81.8% from 318 flights
- July 2026: 76.6% from 330 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 84.9% against 85.8% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 11,039 STL → ATL flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed