Carrier route record
ASSEA→EWR
Alaska Airlines · Seattle to Newark
- Flights
- 1,238
- Period
- July 2025 to June 2026
- Share of route
- 55%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to EWR lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That is a workable record, not a spotless one. That rests on 1,238 flights, with a median arrival 12 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SEA to EWR from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.0%
Arrivals under 15 minutes late, of 1,203 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
2.26%
National rate is 1.81%
Whole route
81.2%
Every carrier on SEA to EWR, 2,235 flights
These figures cover 1,238 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
Alaska against every carrier on SEA to EWR
Alaska flew 1,238 of the 2,235 flights on SEA to EWR, most of the route. Its 81.0% on time is about level with the route as a whole at 81.2%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from United at 81.4% to Alaska at 81.0%.
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 |
|---|---|---|---|---|---|
| United Airlines | 997 | 81.4% | 88 min | 1.10% | B |
| Alaska Airlines (this page) | 1,238 | 81.0% | 54 min | 2.26% | B |
Flight by flight
Alaska flight numbers on SEA to EWR
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 15 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am246 flights90.6%
- 8am–11am593 flights76.1%
- 11am–2pm—
- 2pm–5pm98 flights77.6%
- 5pm–8pm—
- 8pm–5am301 flights83.8%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.6% of the time, against 76.1% for the morning window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 593 flights scheduled in it.
Across the year
Alaska on SEA to EWR through the year
July is the worst month at 60.5% on time, 30 points below April, the best at 90.0%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. May was the busiest month here, with 124 flights.
Across the week, Wednesday is the strongest day at 86.7% on time and Monday the weakest at 77.2%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Alaska runs late on this route
One category carries most of the weight here. National Airspace System accounts for 47% of the 12,000 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.
- 47%National Airspace System
- 28%Carrier
- 17%Late-arriving aircraft
- 9%Extreme weather
- 0%Security
47% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 5,729 minutes out of 12,000, against a national NAS share of 21%. The split is drawn from 12,321 reported delay minutes.
Cancellations sit at 2.26% against a national 1.81%, which is ordinary. Diversions add another 0.57%.
Connections and stage length
What a delay here costs
6.2% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.
At 2,402 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 70.6% on time across 1,237 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.
The sample behind these figures is 1,238 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 SEA to EWR
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 90.0% on time and July 60.5%, a swing of 30 points. If the dates move at all, move them out of July before you think about anything else. 1,203 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to EWR, every carrier
- Alaska on EWR to SEA, the return leg
- United Airlines on SEA to EWR81.4%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Newark Liberty International (EWR) delay statistics
- 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
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.