Route reliability record
DTW→STL
Detroit to St. Louis
- Flights
- 1,905
- Period
- July 2025 to June 2026
- Distance
- 440 mi
- Carriers
- 5
This route lands a B, level with the national rate of 77.6%. Roughly 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 1,905 DTW to STL flights, of which Delta Air Lines flew 1,088 at 80.1% on time.
Best time to fly DTW to STL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 91.6% of the time and Wednesday flights 82.0%, against 77.0% 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
77.0%
Arrivals under 15 minutes late, of 1,881 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
1.00%
National rate is 1.81%
Best carrier
Delta
80.1% on time across 1,088 flights
These figures cover 1,905 flights between July 2025 and June 2026. The median arrival is 7 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 DTW to STL
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 36 | 83.3% | 100 min | 0.00% | B+ |
| Delta Air Lines | 1,088 | 80.1% | 66 min | 1.19% | B |
| Southwest Airlines | 593 | 75.9% | 51 min | 0.51% | B+ |
| SkyWest Airlinesthin sample | 186 | 61.3% | 86 min | 1.61% | D |
| Republic Airwaysthin sample | 2 | 0.0% | 26 min | 0.00% | F+ |
No carrier stands out. Delta tops the table at 80.1%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on DTW to STL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Detroit to St. Louis
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DTW → STLDetroit to St. Louis | Delta Air Lines | 79.1% | 80.1% | 1.19% | 8am–11am, Tue | DL 2822 15:50 |
| 2. DTW → STLDetroit to St. Louis | Southwest Airlines | 75.5% | 75.9% | 0.51% | 8am–11am, Sat | — |
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 26 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am217 flights91.6%
- 8am–11am470 flights82.2%
- 11am–2pm266 flights78.1%
- 2pm–5pm345 flights76.5%
- 5pm–8pm138 flights75.2%
- 8pm–5am469 flights65.3%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.6% of the time, against 65.3% for the overnight window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 470 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 31 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.
December is the weak month at 60.5% on time, against 91.9% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 188 flights.
Across the week, Wednesday is the strongest day at 82.0% on time and Sunday the weakest at 71.7%. 10 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. Carrier accounts for 51% of the 28,000 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.
- 51%Carrier
- 31%Late-arriving aircraft
- 12%National Airspace System
- 6%Extreme weather
- 0%Security
The largest share of delay minutes, 51%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 14,000 of the 28,000 delay minutes reported here. The split is drawn from 27,964 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 91.6% on time here.
Cancellations sit at 1.00% against a national 1.81%, which is ordinary. Diversions add another 0.26%.
Connections and stage length
What a delay here actually costs
7.4% 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.
At 440 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 81.8% on time across 1,905 flights, 5 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.
The sample behind these figures is 1,905 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 STL 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. September runs 91.9% on time and December 60.5%, a swing of 31 points. If the dates move at all, move them out of December before you think about anything else. 1,881 completed flights over 12 months sit behind that.
Common questions
DTW to STL questions
How often is DTW to STL delayed?
Roughly 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 23.0% of the 1,905 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DTW to STL?
Delta Air Lines leads at 80.1% on time across 1,088 flights. Southwest Airlines is at the other end on 75.9%, a gap of 4 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DTW to STL?
The 5am–8am departure window is the strongest at 91.6% on time. The 8pm–5am window is the weakest at 65.3%, 26 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 December delays on DTW to STL?
December is the weakest month at 60.5% on time, compared with 91.9% in September. Across the year that is 31 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
- STL to DTW — the return legseparate record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Delta Air Lines on DTW to STL80.1%
- Southwest Airlines on DTW to STL75.9%
- SkyWest Airlines on DTW to STL61.3%
- DTW to ORD, a related route72.0%
- ATL to STL, a related route82.4%
- DTW to ATL, a related route79.0%
- Spirit Airlines on-time record83.3%
- Delta Air Lines on-time record80.1%
- Southwest Airlines on-time record75.9%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. DTW to STL and STL to DTW 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.