Route reliability record
STL→DAL
St. Louis to Dallas
- Flights
- 1,925
- Period
- July 2025 to June 2026
- Distance
- 546 mi
- Carriers
- 1
This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,925 STL to DAL flights, with a median arrival 4 minutes early.
Best time to fly STL to DAL: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 92.4% of the time and Tuesday flights 84.8%, against 76.2% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.2%
Arrivals under 15 minutes late, of 1,885 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
1.51%
National rate is 1.81%
Best carrier
Southwest
76.2% on time across 1,925 flights
These figures cover 1,925 flights between July 2025 and June 2026. The median arrival is 4 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on STL to DAL
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 1,925 | 76.2% | 61 min | 1.51% | B |
Best ways to make this trip
The most reliable ways to fly St. Louis to Dallas
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. STL → DALSt. Louis to Dallas | Southwest Airlines | 75.0% | 76.2% | 1.51% | 5am–8am, Tue | — |
| 2. STL → DFWSt. Louis to Dallas-Fort Worth | American Airlines | 72.2% | 74.8% | 3.46% | 5am–8am, Tue | AA 2261 05:20 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 33 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am368 flights92.4%
- 8am–11am359 flights89.0%
- 11am–2pm239 flights80.0%
- 2pm–5pm402 flights67.6%
- 5pm–8pm283 flights64.3%
- 8pm–5am274 flights59.6%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.6% on time, against 92.4% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 2pm–5pm window is the busiest, with 402 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 35 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 56.0% on time, 35 points below January, the best at 90.5%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 173 flights.
Across the week, Tuesday is the strongest day at 84.8% on time and Sunday the weakest at 66.9%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 47% of the 27,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 47%Late-arriving aircraft
- 30%Carrier
- 19%National Airspace System
- 4%Extreme weather
- 0%Security
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 27,000 reported delay minutes here, that single category outweighs weather by 10 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 27,213 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.4% on time here.
Cancellations sit at 1.51% against a national 1.81%, which is ordinary. Diversions add another 0.57%.
Connections and stage length
What a delay here actually costs
7.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 546 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 76.8% on time across 1,922 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,925 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DAL after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 90.5% on time and June 56.0%, a swing of 35 points. If the dates move at all, move them out of June before you think about anything else. 1,885 completed flights over 12 months sit behind that.
Common questions
STL to DAL questions
How often is STL to DAL delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.8% of the 1,925 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is STL to DAL compared with the rest of the country?
76.2% of flights arrive on time here against a national 77.6%, a difference of about a point against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on STL to DAL?
The 5am–8am departure window is the strongest at 92.4% on time. The 8pm–5am window is the weakest at 59.6%, 33 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on STL to DAL?
June is the weakest month at 56.0% on time, compared with 90.5% in January. Across the year that is 35 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DAL to STL — the return legseparate record
- St. Louis Lambert International (STL) delay statistics
- Dallas Love Field (DAL) delay statistics
- STL to ATL, a related route85.3%
- HOU to DAL, a related route80.9%
- STL to DEN, a related route74.9%
- Southwest Airlines on-time record76.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. STL to DAL and DAL to STL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.