Carrier route record
UASEA→EWR
United Airlines · Seattle to Newark
- Flights
- 997
- Period
- July 2025 to June 2026
- Share of route
- 45%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SEA to EWR lands a B, 4 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 an hour and a half on average. That is a workable record, not a spotless one. That rests on 997 flights, with a median arrival 13 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate United 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
81.4%
Arrivals under 15 minutes late, of 984 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.81%
Whole route
81.2%
Every carrier on SEA to EWR, 2,235 flights
These figures cover 997 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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
United against every carrier on SEA to EWR
United flew 997 of the 2,235 flights on SEA to EWR, about 45% of it. Its 81.4% on time is about level with the route as a whole at 81.2%. Ranked by on-time rate it is first 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 (this page) | 997 | 81.4% | 88 min | 1.10% | B |
| Alaska Airlines | 1,238 | 81.0% | 54 min | 2.26% | B |
Flight by flight
United flight numbers on SEA to EWR
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 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–8am285 flights94.3%
- 8am–11am—
- 11am–2pm247 flights68.4%
- 2pm–5pm106 flights72.4%
- 5pm–8pm—
- 8pm–5am359 flights82.7%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 68.4% on time against 94.3% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8pm–5am window is the busiest, with 359 flights scheduled in it.
Across the year
United on SEA to EWR through the year
July is the worst month at 60.8% on time, 34 points below January, the best at 94.5%. 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. July was the busiest month here, with 124 flights.
Across the week, Tuesday is the strongest day at 87.4% on time and Sunday the weakest at 76.2%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. National Airspace System accounts for 50% of the 16,000 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.
- 50%National Airspace System
- 24%Carrier
- 21%Late-arriving aircraft
- 5%Extreme weather
50% 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 8,074 minutes out of 16,000, against a national NAS share of 21%. The split is drawn from 16,061 reported delay minutes.
Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.20%.
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. 9.7% 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 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 77.1% on time across 997 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 997 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.
What to do with this
Booking United on SEA to EWR
Put together: treat all of this as provisional. 997 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 81.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 984 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to EWR, every carrier
- United on EWR to SEA, the return leg
- Alaska Airlines on SEA to EWR81.0%
- United 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
- How often a connection fails at the major US hubs
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.