Carrier route record
DLSEA→PHX
Delta Air Lines · Seattle to Phoenix
- Flights
- 1,765
- Period
- July 2025 to June 2026
- Share of route
- 24%
- Carriers
- 7
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SEA to PHX lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,765 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 691 at 86.9% on time.
Envoy Air is the most reliable of the four carriers covered here at 86.9% on time across 691 flights.
Key figures
On time
82.6%
Arrivals under 15 minutes late, of 1,744 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.81%
Whole route
79.2%
Every carrier on SEA to PHX, 7,268 flights
These figures cover 1,765 flights between July 2025 and June 2026. The median arrival is 8 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
Delta against every carrier on SEA to PHX
Delta flew 1,765 of the 7,268 flights on SEA to PHX, about 24% of it. Its 82.6% on time is 3 points better than the route as a whole, which runs 79.2%. Ranked by on-time rate it is number three of seven carriers on the route, where the range runs from Envoy at 86.9% to Southwest at 69.0%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Envoy Air arrives on time 86.9% of the time; Southwest Airlines manages 69.0%. Sample sizes sit next to every figure, because a two-point gap across 1,036 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Air | 691 | 86.9% | 71 min | 0.00% | A+ |
| American Airlinesthin sample | 199 | 84.8% | 81 min | 0.50% | B+ |
| Delta Air Lines (this page) | 1,765 | 82.6% | 65 min | 0.85% | B+ |
| SkyWest Airlines | 506 | 80.2% | 75 min | 0.59% | B+ |
| Alaska Airlines | 2,906 | 79.0% | 45 min | 0.65% | B+ |
| Frontier Airlinesthin sample | 165 | 70.4% | 126 min | 3.64% | C− |
| Southwest Airlines | 1,036 | 69.0% | 47 min | 0.68% | C+ |
The spread between Envoy and Southwest is 18 points, wide enough that it should decide the booking. On a hundred trips that is 18 more arrivals inside the on-time window.
Flight by flight
Delta flight numbers on SEA to PHX
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am251 flights92.4%
- 8am–11am364 flights84.4%
- 11am–2pm450 flights83.9%
- 2pm–5pm247 flights77.0%
- 5pm–8pm242 flights76.1%
- 8pm–5am211 flights78.7%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.4% of the time, against 76.1% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 450 flights scheduled in it.
Across the year
Delta on SEA to PHX through the year
December is the weak month at 72.2% on time, against 88.9% in July. 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. October was the busiest month here, with 154 flights.
Across the week, Wednesday is the strongest day at 87.1% on time and Monday the weakest at 77.9%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Carrier accounts for 58% of the 20,000 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.
- 58%Carrier
- 20%Late-arriving aircraft
- 19%National Airspace System
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 58%, 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 11,000 of the 20,000 delay minutes reported here. The split is drawn from 19,894 reported delay minutes.
Cancellations are rare at 0.85%, below the national 1.81% 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 costs
5.7% 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 about an hour, which a normal layover absorbs.
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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 87.8% on time across 1,764 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 1,765 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 Delta on SEA to PHX
Put together: the calendar is the biggest lever here, not the carrier or the hour. July runs 88.9% on time and December 72.2%, a swing of 17 points. If the dates move at all, move them out of December before you think about anything else. 1,744 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to PHX, every carrier
- Delta on PHX to SEA, the return leg
- Envoy Air on SEA to PHX86.9%
- American Airlines on SEA to PHX84.8%
- SkyWest Airlines on SEA to PHX80.2%
- Alaska Airlines on SEA to PHX79.0%
- Frontier Airlines on SEA to PHX70.4%
- Southwest Airlines on SEA to PHX69.0%
- Delta Air Lines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.04 million flight records
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.