Route reliability record
PHX→SEA
Phoenix to Seattle
- Flights
- 7,202
- Period
- September 2025 to August 2026
- Distance
- 1,107 mi
- Carriers
- 7
This route lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 7,202 PHX to SEA flights, of which Envoy Air flew 761 at 87.6% on time.
Best time to fly PHX to SEA: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 90.6% of the time and Saturday flights 85.1%, against 82.2% for the route overall.
Envoy Air is the most reliable of the five carriers covered here at 87.6% on time across 761 flights.
Key figures
On time
82.2%
Arrivals under 15 minutes late, of 7,138 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.69%
National rate is 1.89%
Best carrier
Envoy
87.6% on time across 761 flights
These figures cover 7,202 flights between September 2025 and August 2026. The median arrival is 7 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.
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Carrier by carrier
Which airline is most reliable on PHX to SEA
The choice of carrier is not cosmetic here. Envoy Air arrives on time 87.6% of the time; Southwest Airlines manages 62.2%. Sample sizes sit next to every figure, because a two-point gap across 1,039 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Air | 761 | 87.6% | 50 min | 0.00% | A+ |
| Delta Air Lines | 1,767 | 87.5% | 75 min | 0.96% | A+ |
| Alaska Airlines | 2,886 | 84.4% | 56 min | 0.76% | B+ |
| Frontier Airlinesthin sample | 116 | 83.6% | 83 min | 0.00% | B+ |
| SkyWest Airlines | 409 | 83.0% | 63 min | 0.49% | B+ |
| American Airlinesthin sample | 224 | 82.5% | 63 min | 0.45% | B+ |
| Southwest Airlines | 1,039 | 62.2% | 45 min | 0.77% | D+ |
The spread between Envoy and Southwest is 25 points, wide enough that it should decide the booking. On a hundred trips that is 25 more arrivals inside the on-time window.
Flight by flight
Flights on PHX to SEA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Phoenix to Seattle
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PHX → SEAPhoenix to Seattle | Envoy Air | 87.6% | 87.6% | 0.00% | 5am–8am, Mon | — |
| 2. PHX → SEAPhoenix to Seattle | Delta Air Lines | 86.7% | 87.5% | 0.96% | 5am–8am, Sat | DL 2444 08:00 |
| 3. PHX → SEAPhoenix to Seattle | Alaska Airlines | 83.8% | 84.4% | 0.76% | 5am–8am, Sun | AS 603 11:23 |
| 4. PHX → SEAPhoenix to Seattle | SkyWest Airlines | 82.6% | 83.0% | 0.49% | 5am–8am, Sat | — |
| 5. PHX → SEAPhoenix to Seattle | Southwest Airlines | 61.7% | 62.2% | 0.77% | 8am–11am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 22 points, against 25 points between the best and worst carrier.
- 5am–8am1,253 flights90.6%
- 8am–11am1,307 flights80.9%
- 11am–2pm1,323 flights86.7%
- 2pm–5pm1,524 flights80.2%
- 5pm–8pm1,278 flights78.3%
- 8pm–5am517 flights68.4%
Scale runs 60% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.6% of the time, against 68.4% for the overnight window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 1,524 flights scheduled in it.
Explore
Filter PHX to SEA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On PHX to SEA, the best departure window is 5am–8am at 90.6% on time and the worst is 8pm–5am at 68.4%, a wide gap of 22.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am90.6%
- 8–11am80.9%
- 11am–2pm86.7%
- 2–5pm80.2%
- 5–8pm78.3%
- 8pm–5am68.4%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 13 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.
August is the worst month at 76.9% on time, 13 points below February, the best at 90.3%. 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. March was the busiest month here, with 685 flights.
Across the week, Saturday is the strongest day at 85.1% on time and Thursday the weakest at 80.0%, a spread of 5 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 47% of the 72,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 33%Carrier
- 16%National Airspace System
- 4%Extreme weather
- 0%Security
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 72,000 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 71,650 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 90.6% on time here.
Cancellations are rare at 0.69%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.6% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,107 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 78.2% on time across 7,205 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.
The sample behind these figures is 7,202 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.
Work out the risk of missing a connection in SEA after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 90.3% on time and August 76.9%, a swing of 13 points. If the dates move at all, move them out of August before you think about anything else. 7,138 completed flights over 12 months sit behind that.
Common questions
PHX to SEA questions
How often is PHX to SEA delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.8% of the 7,202 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PHX to SEA?
Envoy Air leads at 87.6% on time across 761 flights. Southwest Airlines is at the other end on 62.2%, a gap of 25 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 PHX to SEA?
The 5am–8am departure window is the strongest at 90.6% on time. The 8pm–5am window is the weakest at 68.4%, 22 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 August delays on PHX to SEA?
August is the weakest month at 76.9% on time, compared with 90.3% in February. Across the year that is 13 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
- SEA to PHX — the return legseparate record
- Phoenix Sky Harbor International (PHX) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Envoy Air on PHX to SEA87.6%
- Delta Air Lines on PHX to SEA87.5%
- Alaska Airlines on PHX to SEA84.4%
- Frontier Airlines on PHX to SEA83.6%
- SkyWest Airlines on PHX to SEA83.0%
- American Airlines on PHX to SEA82.5%
- Southwest Airlines on PHX to SEA62.2%
- PHX to DEN, a related route76.7%
- LAX to SEA, a related route85.0%
- PHX to LAX, a related route82.1%
- Envoy Air on-time record87.6%
- Delta Air Lines on-time record87.5%
- Alaska Airlines on-time record84.4%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. PHX to SEA and SEA to PHX are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.