Route profile
DTW→SEA
Flight reliability, delays and best times to fly from Detroit to Seattle, 1,927 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 80% of comparable major US routes (4,598 compared)
Calculated from 6,423 flights. How this is calculated
DTW → SEA arrives on time 80.4% of the time; the return trip, SEA → DTW, arrives on time 85.3% of the time, a 4.9-point gap between the two directions of the same city pair.
DTW → SEA spends 30.4 minutes on the ground on a 1,927-mile trip: 18.0 minutes from pushback to wheels-up at DTW and 12.4 minutes from touchdown to gate at SEA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Reliability on this route has fallen unusually sharply over the past year, a bigger swing than 94% of 5,368 comparable routes.
73.1% on time over the most recent 12 months (2025-08 to 2026-07), against 84.4% in the 12 months before (2024-08 to 2025-07), a change of 11.3 points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 5,368 in the comparison.
What sets this route apart
Where DTW to SEA differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
DTW to SEA is at its best against routes of similar length for flights scheduled at 7 PM: 78.6% arrive on time, 11.5 points ahead of the 67.1% those routes manage at that hour. Against all other routes the gap is 10.8 points.
DTW to SEA struggles most at 7 AM: 81.7% of its flights scheduled then arrive on time, 5.1 points behind the 86.8% on routes of similar length at the same hour. Against all other routes the gap is 6.1 points.
DTW to SEA holds up on Sundays better than routes of similar length do: 79.0% on time to their 75.6%, a 3.4 points lead. Against all other routes the gap is 4.2 points.
July is kinder to DTW to SEA than to routes of similar length: 78.1% on time against 70.4%, 7.7 points better. Against all other routes the gap is 8.4 points.
In December, DTW to SEA runs 7.5 points below routes of similar length, 72.5% on time to 80.0%. Against all other routes the gap is 6.3 points.
DTW to SEA against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 7 PM departures | 78.6% | routes of similar length | 67.1% | +11.5 pts | 271 here, 41,150 there |
| Hour: 7 AM departures | 81.7% | routes of similar length | 86.8% | −5.1 pts | 493 here, 103,928 there |
| Weekday: Sunday | 79.0% | routes of similar length | 75.6% | +3.4 pts | 946 here, 157,688 there |
| Month: July | 78.1% | routes of similar length | 70.4% | +7.7 pts | 899 here, 130,061 there |
| Month: December | 72.5% | routes of similar length | 80.0% | −7.5 pts | 469 here, 84,765 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,927 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
33 min late
against a median of 7 min early
Percentiles over 6,423 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SEA after arriving from DTW.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 37% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 11% | Some risk |
| 90 min | 4.8% | Low risk |
| 120 min | 2.6% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.65% of the time and diverts 0.14% of the time, which a late arrival never shows up in.
Chance of missing is the share of 6,372 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 33 minutes late (90th-percentile gate arrival delay), over 6,423 operations.
Any other layover length: connection checker.
Best time to fly
DTW → SEA flights departing 5–9 AM arrived on time 85.6% of the time, against 72.1% for 6–9 PM departures, a gap of 13.5 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 88.1% on time from 339 flights
- 7 AM: 81.7% on time from 496 flights
- 8 AM: 86.5% on time from 1,097 flights
- 9 AM to 11 AM: too few flights to score
- 12 PM: 84.8% on time from 1,096 flights
- 1 PM to 2 PM: too few flights to score
- 3 PM: 78.6% on time from 129 flights
- 4 PM: 78.8% on time from 1,354 flights
- 5 PM: 82.3% on time from 294 flights
- 6 PM: 73.2% on time from 455 flights
- 7 PM: 78.6% on time from 271 flights
- 8 PM: 69.3% on time from 823 flights
- 9 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why DTW → SEA runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for DTW → SEA. Only delays of 15 minutes or more are attributed.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 4,795 | 81.1% | 0.63% | -8 min | 4.8% |
| Alaska Airlines | 1,627 | 78.1% | 0.74% | -3 min | 5.1% |
Delta Air Lines flew 74.7% of the 6,422 flights listed.
Delta Air Lines arrived on time 3.0 percentage points more often than Alaska Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
DL728 (12:15 PM) arrived on time 84.8% of the time, 15.8 points more often than DL565 (8:20 PM) at 69.0%.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 6.7 percentage points.
By month
- Jan: 76.5%
- Feb: 81.4%
- Mar: 73.0%
- Apr: 85.0%
- May: 80.0%
- Jun: 72.8%
- Jul: 78.1%
- Aug: 82.3%
- Sep: 90.0%
- Oct: 89.7%
- Nov: 83.8%
- Dec: 72.5%
December is historically the weakest month and September the strongest, a spread of 17.5 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 76.5% from 238 flights
- August 2023: 85.6% from 224 flights
- September 2023: 90.0% from 200 flights
- October 2023: 93.6% from 157 flights
- November 2023: 88.2% from 144 flights
- December 2023: 95.5% from 154 flights
- January 2024: 77.4% from 131 flights
- February 2024: 95.0% from 120 flights
- March 2024: 85.1% from 142 flights
- April 2024: 87.6% from 146 flights
- May 2024: 73.2% from 194 flights
- June 2024: 63.5% from 222 flights
- July 2024: 82.6% from 234 flights
- August 2024: 77.8% from 223 flights
- September 2024: 90.3% from 208 flights
- October 2024: 88.2% from 161 flights
- November 2024: 91.8% from 147 flights
- December 2024: 86.3% from 153 flights
- January 2025: 84.4% from 122 flights
- February 2025: too few flights to score (108)
- March 2025: 87.2% from 141 flights
- April 2025: 85.7% from 147 flights
- May 2025: 91.4% from 197 flights
- June 2025: 78.8% from 218 flights
- July 2025: 76.2% from 228 flights
- August 2025: 83.5% from 214 flights
- September 2025: 89.8% from 176 flights
- October 2025: 87.3% from 159 flights
- November 2025: 72.1% from 154 flights
- December 2025: 37.7% from 164 flights
- January 2026: 68.4% from 135 flights
- February 2026: 70.7% from 125 flights
- March 2026: 47.2% from 151 flights
- April 2026: 81.9% from 155 flights
- May 2026: 75.6% from 206 flights
- June 2026: 76.6% from 209 flights
- July 2026: 77.1% from 216 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 73.1% against 84.4% in the 12 months before — declining by 11.3 percentage points.
Data and methodology
Calculated by FlyerIntel from 6,423 DTW → SEA flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed