Route reliability record
EWR→SFO
Newark to San Francisco
- Flights
- 4,403
- Period
- July 2025 to June 2026
- Distance
- 2,565 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 4,403 flights, of which Alaska Airlines flew 610 at 75.5% on time.
The national on-time rate over the same period is 77.6%, so this route runs 8 points behind the country as a whole. Across a thousand flights that is about 78 extra late arrivals.
Key figures
On time
69.8%
Arrivals under 15 minutes late, of 4,290 completed flights
Avg delay
89 min
Across delayed arrivals only, not all flights
Cancelled
2.32%
National rate is 1.81%
Best carrier
Alaska
75.5% on time across 610 flights
These figures cover 4,403 flights between July 2025 and June 2026. Beyond the headline rate, 12.9% 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
Which airline is most reliable on EWR to SFO
The choice of carrier is not cosmetic here. Alaska Airlines arrives on time 75.5% of the time; United Airlines manages 68.9%. Sample sizes sit next to every figure, because a two-point gap across 3,793 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 610 | 75.5% | 69 min | 0.98% | B+ |
| United Airlines | 3,793 | 68.9% | 92 min | 2.53% | C |
Alaska leads United by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 20 points, against 7 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am844 flights78.7%
- 8am–11am914 flights74.1%
- 11am–2pm584 flights71.4%
- 2pm–5pm865 flights70.0%
- 5pm–8pm914 flights59.4%
- 8pm–5am282 flights58.6%
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 58.6% on time, against 78.7% for the 5am–8am 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 914 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 30 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.
June is the worst month at 51.5% on time, 30 points below March, the best at 81.2%. 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 404 flights.
Across the week, Tuesday is the strongest day at 78.3% on time and Sunday the weakest at 64.3%. 14 points is a smaller lever than departure hour, but it is free.
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 116,000 reported delay minutes.
- 34%Carrier
- 32%Late-arriving aircraft
- 29%National Airspace System
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 40,000 of the 116,000 delay minutes reported here. The split is drawn from 115,510 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 78.7% on time here.
Cancellations sit at 2.32% against a national 1.81%, which is ordinary. Diversions add another 0.25%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.9% 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 2,565 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 76.4% on time across 4,401 flights, 7 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 7 points of difference.
The sample behind these figures is 4,403 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 81.2% on time and June 51.5%, a swing of 30 points. If the dates move at all, move them out of June before you think about anything else. 4,290 completed flights over 12 months sit behind that.
Common questions
EWR to SFO questions
How often is EWR to SFO delayed?
Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 30.2% of the 4,403 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on EWR to SFO?
Alaska Airlines leads at 75.5% on time across 610 flights. United Airlines is at the other end on 68.9%, a gap of 7 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on EWR to SFO?
The 5am–8am departure window is the strongest at 78.7% on time. The 8pm–5am window is the weakest at 58.6%, 20 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 June delays on EWR to SFO?
June is the weakest month at 51.5% on time, compared with 81.2% in March. Across the year that is 30 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
- SFO to EWR — the return legseparate record
- Newark Liberty International (EWR) delay statistics
- San Francisco International (SFO) delay statistics
- Alaska Airlines on-time record75.5%
- United Airlines on-time record68.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. EWR to SFO and SFO to EWR are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.