Route reliability record
DTW→SAT
Detroit to San Antonio
- Flights
- 934
- Period
- September 2025 to August 2026
- Distance
- 1,214 mi
- Carriers
- 1
This route lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 934 DTW to SAT flights, with a median arrival 10 minutes early.
Best time to fly DTW to SAT: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 87.6% of the time and Tuesday flights 87.7%, against 80.4% for the route overall.
The US average over the same twelve months is 77.3%, 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
80.4%
Arrivals under 15 minutes late, of 924 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.75%
National rate is 1.89%
Best carrier
Delta
80.4% on time across 934 flights
These figures cover 934 flights between September 2025 and August 2026. The median arrival is 10 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.
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Carrier by carrier
Which airline is most reliable on DTW to SAT
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 934 | 80.4% | 56 min | 0.75% | B+ |
Flight by flight
Flights on DTW to SAT
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.
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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 17 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am326 flights87.6%
- 11am–2pm247 flights84.6%
- 2pm–5pm6 flights—
- 5pm–8pm—
- 8pm–5am355 flights70.4%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 87.6% of the time, against 70.4% for the overnight window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 355 flights scheduled in it.
Explore
Filter DTW to SAT by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DTW to SAT, the best departure window is 8am–11am at 87.6% on time and the worst is 8pm–5am at 70.4%, a wide gap of 17.2 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am87.6%
- 11am–2pm84.6%
- 2–5pm—
- 5–8pm—
- 8pm–5am70.4%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 29 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.
January is the weak month at 61.9% on time, against 90.4% in October. 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. May was the busiest month here, with 87 flights.
Across the week, Tuesday is the strongest day at 87.7% on time and Friday the weakest at 76.5%, a spread of 11 points.
Delay causes
Why this route gets delayed
Carrier accounts for 57% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 57%Carrier
- 23%National Airspace System
- 17%Late-arriving aircraft
- 3%Extreme weather
The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 5,740 of the 10,000 delay minutes reported here. The split is drawn from 10,068 reported delay minutes.
Cancellations are rare at 0.75%, below the national 1.89% 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
6.0% of arrivals land an hour or more late, close to the national 8.3%, so 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 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.
The return leg is a different operation and performs like one: it runs 90.7% on time across 934 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 934 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 SAT after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 934 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 80.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 924 completed flights over 12 months sit behind that.
Common questions
DTW to SAT questions
How often is DTW to SAT delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.6% of the 934 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is DTW to SAT compared with the rest of the country?
80.4% of flights arrive on time here against a national 77.3%, a difference of 3 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DTW to SAT?
The 8am–11am departure window is the strongest at 87.6% on time. The 8pm–5am window is the weakest at 70.4%, 17 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 January delays on DTW to SAT?
January is the weakest month at 61.9% on time, compared with 90.4% in October. Across the year that is 29 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
- SAT to DTW — the return legseparate record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- San Antonio International (SAT) delay statistics
- DTW to ORD, a related route72.2%
- DFW to SAT, a related route67.8%
- DTW to ATL, a related route78.9%
- Delta Air Lines on-time record80.4%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. DTW to SAT and SAT 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.