Route reliability record
SAT→DTW
San Antonio to Detroit
- Flights
- 951
- Period
- July 2025 to June 2026
- Distance
- 1,214 mi
- Carriers
- 2
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 951 SAT to DTW flights, with a median arrival 12 minutes early.
Best time to fly SAT to DTW: a 5am–8am departure, ideally on a Friday. Flights in that window arrived on time 95.0% of the time and Friday flights 92.2%, against 90.2% for the route overall.
Set against the rest of the country, this route's record is 13 points better than the US average of 77.6%. That gap is worth roughly 126 fewer late arrivals for every thousand flights.
Key figures
On time
90.2%
Arrivals under 15 minutes late, of 941 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.81%
Best carrier
Delta
90.2% on time across 934 flights
These figures cover 951 flights between July 2025 and June 2026. The median arrival is 12 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 SAT to DTW
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 |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 17 | 94.1% | 306 min | 0.00% | A+ |
| Delta Air Lines | 934 | 90.2% | 72 min | 0.75% | A+ |
Flight by flight
Flights on SAT to DTW
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.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 951 flights.
- 5am–8am362 flights95.0%
- 8am–11am13 flights—
- 11am–2pm221 flights89.9%
- 2pm–5pm354 flights85.5%
- 5pm–8pm1 flights—
- 8pm–5am—
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.0% of the time, against 85.5% for the afternoon window. That is 10 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 362 flights scheduled in it.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 951 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
February is the weak month at 83.9% on time, against 95.1% in June. 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. August was the busiest month here, with 97 flights.
Across the week, Friday is the strongest day at 92.2% on time and Sunday the weakest at 87.7%. 5 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 53% of the 6,879 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.
- 53%Carrier
- 30%Late-arriving aircraft
- 16%National Airspace System
- 1%Extreme weather
- 1%Security
The largest share of delay minutes, 53%, 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 3,627 of the 6,879 delay minutes reported here. The split is drawn from 6,879 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 95.0% on time here.
Cancellations are rare at 0.74%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,214 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 is a different operation and performs like one: it runs 80.1% on time across 951 flights, 10 points below 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 10 points of difference.
One caution: this is a thin sample. 951 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in DTW after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 951 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 90.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 941 completed flights over 12 months sit behind that.
Common questions
SAT to DTW questions
How often is SAT to DTW delayed?
About one flight in ten arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 9.8% of the 951 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is SAT to DTW compared with the rest of the country?
90.2% of flights arrive on time here against a national 77.6%, a difference of 13 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on SAT to DTW?
The 5am–8am departure window is the strongest at 95.0% on time. The 2pm–5pm window is the weakest at 85.5%, 10 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 February delays on SAT to DTW?
February is the weakest month at 83.9% on time, compared with 95.1% in June. Across the year that is 11 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
- DTW to SAT — the return legseparate record
- San Antonio International (SAT) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- SAT to DFW, a related route77.1%
- ORD to DTW, a related route70.6%
- SAT to DEN, a related route81.0%
- Spirit Airlines on-time record94.1%
- Delta Air Lines on-time record90.2%
- 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. SAT to DTW and DTW to SAT 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.