Carrier route record
ASORD→SEA
Alaska Airlines · Chicago to Seattle
- Flights
- 1,799
- Period
- July 2025 to June 2026
- Share of route
- 32%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on ORD to SEA draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,799 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,535 at 73.6% on time.
United Airlines is the most reliable of the three carriers covered here at 73.6% on time across 1,535 flights.
Key figures
On time
67.5%
Arrivals under 15 minutes late, of 1,764 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
1.67%
National rate is 1.81%
Whole route
68.5%
Every carrier on ORD to SEA, 5,572 flights
These figures cover 1,799 flights between July 2025 and June 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Alaska against every carrier on ORD to SEA
Alaska flew 1,799 of the 5,572 flights on ORD to SEA, about 32% of it. Its 67.5% on time is about level with the route as a whole at 68.5%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 73.6% to American at 63.5%.
The choice of carrier is not cosmetic here. United Airlines arrives on time 73.6% of the time; American Airlines manages 63.5%. Sample sizes sit next to every figure, because a two-point gap across 1,336 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,535 | 73.6% | 59 min | 0.72% | C+ |
| Delta Air Lines | 902 | 68.8% | 66 min | 1.44% | C |
| Alaska Airlines (this page) | 1,799 | 67.5% | 63 min | 1.67% | C |
| American Airlines | 1,336 | 63.5% | 70 min | 2.02% | D |
United leads American by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Alaska flight numbers on ORD to SEA
Departure window
When Alaska runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am334 flights81.5%
- 8am–11am481 flights67.2%
- 11am–2pm160 flights82.3%
- 2pm–5pm358 flights67.4%
- 5pm–8pm382 flights53.0%
- 8pm–5am84 flights50.0%
Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 50.0% on time, against 82.3% for the 11am–2pm 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 481 flights scheduled in it.
Across the year
Alaska on ORD to SEA through the year
December is the weak month at 48.5% on time, against 81.4% in May. 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 211 flights.
Across the week, Saturday is the strongest day at 70.3% on time and Sunday the weakest at 65.3%. 5 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Alaska runs late on this route
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 36,000 reported delay minutes.
- 42%Late-arriving aircraft
- 30%National Airspace System
- 22%Carrier
- 6%Extreme weather
- 0%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 36,000 reported delay minutes here, that single category outweighs weather by 7 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 35,881 reported delay minutes.
Cancellations sit at 1.67% against a national 1.81%, which is ordinary. Diversions add another 0.28%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.8% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 1,721 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 72.3% on time across 1,794 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 1,799 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.
What to do with this
Booking Alaska on ORD to SEA
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 81.4% on time and December 48.5%, a swing of 33 points. If the dates move at all, move them out of December before you think about anything else. 1,764 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to SEA, every carrier
- Alaska on SEA to ORD, the return leg
- United Airlines on ORD to SEA73.6%
- Delta Air Lines on ORD to SEA68.8%
- American Airlines on ORD to SEA63.5%
- Alaska Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.