Route reliability record
DTW→SAN
Detroit to San Diego
- Flights
- 1,269
- Period
- September 2025 to August 2026
- Distance
- 1,956 mi
- Carriers
- 2
This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 1,269 DTW to SAN flights, with a median arrival right on schedule.
Best time to fly DTW to SAN: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 83.1% of the time and Wednesday flights 79.9%, against 73.5% 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
73.5%
Arrivals under 15 minutes late, of 1,250 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.87%
National rate is 1.89%
Best carrier
Delta
73.3% on time across 1,250 flights
These figures cover 1,269 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Carrier by carrier
Which airline is most reliable on DTW to SAN
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 | 19 | 88.2% | 33 min | 5.26% | A− |
| Delta Air Lines | 1,250 | 73.3% | 60 min | 0.80% | C+ |
Flight by flight
Flights on DTW to SAN
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 25 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am384 flights83.1%
- 11am–2pm260 flights74.3%
- 2pm–5pm317 flights73.8%
- 5pm–8pm47 flights57.8%
- 8pm–5am261 flights61.1%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 57.8% on time, against 83.1% for the 8am–11am 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 8am–11am window is the busiest, with 384 flights scheduled in it.
Explore
Filter DTW to SAN 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 SAN, the best departure window is 8am–11am at 83.1% on time and the worst is 5pm–8pm at 57.8%, a wide gap of 25.3 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am83.1%
- 11am–2pm74.3%
- 2–5pm73.8%
- 5–8pm57.8%
- 8pm–5am61.1%
best all US flightsScale 50% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 28 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 57.1% on time, against 84.7% 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. September was the busiest month here, with 119 flights.
Across the week, Wednesday is the strongest day at 79.9% on time and Thursday the weakest at 67.7%, a spread of 12 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 20,000 reported delay minutes.
- 39%Carrier
- 30%National Airspace System
- 26%Late-arriving aircraft
- 4%Extreme weather
- 1%Security
The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,832 of the 20,000 delay minutes reported here. The split is drawn from 19,879 reported delay minutes.
Cancellations are rare at 0.87%, 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
7.7% 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.
At 1,956 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 85.9% on time across 1,269 flights, 12 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 12 points of difference.
The sample behind these figures is 1,269 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 SAN 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. October runs 84.7% on time and January 57.1%, a swing of 28 points. If the dates move at all, move them out of January before you think about anything else. 1,250 completed flights over 12 months sit behind that.
Common questions
DTW to SAN questions
How often is DTW to SAN 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 26.5% of the 1,269 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is DTW to SAN compared with the rest of the country?
73.5% of flights arrive on time here against a national 77.3%, a difference of 4 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on DTW to SAN?
The 8am–11am departure window is the strongest at 83.1% on time. The 5pm–8pm window is the weakest at 57.8%, 25 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 SAN?
January is the weakest month at 57.1% on time, compared with 84.7% in October. Across the year that is 28 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
- SAN to DTW — the return legseparate record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- San Diego International (SAN) delay statistics
- DTW to ORD, a related route72.2%
- SFO to SAN, a related route62.2%
- DTW to ATL, a related route78.9%
- Spirit Airlines on-time record88.2%
- Delta Air Lines on-time record73.3%
- 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 SAN and SAN 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.