Carrier route record

DLSEA→PHX

Delta Air Lines · Seattle to Phoenix

Flights: 1,768
Period: September 2025 to August 2026
Share of route: 25%
Carriers: 7

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on SEA to PHX lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,768 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 760 at 85.3% on time.

Envoy Air is the most reliable of the four carriers covered here at 85.3% on time across 760 flights.

On time

80.9%

Arrivals under 15 minutes late, of 1,741 completed flights

Avg delay

67 min

Across delayed arrivals only, not all flights

Cancelled

0.96%

National rate is 1.89%

Whole route

78.2%

Every carrier on SEA to PHX, 7,205 flights

These figures cover 1,768 flights between September 2025 and August 2026. The median arrival is 6 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

Delta against every carrier on SEA to PHX

Delta flew 1,768 of the 7,205 flights on SEA to PHX, about 25% of it. Its 80.9% on time is 3 points better than the route as a whole, which runs 78.2%. Ranked by on-time rate it is number three of seven carriers on the route, where the range runs from Envoy at 85.3% to Southwest at 65.1%. 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 85.3% of the time; Southwest Airlines manages 65.1%. Sample sizes sit next to every figure, because a two-point gap across 1,042 flights means less than a ten-point one.

On-time performance by carrier on SEA to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Air	760	85.3%	74 min	0.00%	A+
American Airlinesthin sample	221	83.2%	76 min	0.45%	B+
Delta Air Lines (this page)	1,768	80.9%	67 min	0.96%	B+
Alaska Airlines	2,889	79.2%	45 min	0.66%	B+
SkyWest Airlines	409	78.5%	80 min	0.49%	B+
Frontier Airlinesthin sample	116	74.5%	146 min	5.17%	C−
Southwest Airlines	1,042	65.1%	49 min	0.77%	C+

The spread between Envoy and Southwest is 20 points, wide enough that it should decide the booking. On a hundred trips that is 20 more arrivals inside the on-time window.

Flight by flight

Delta flight numbers on SEA to PHX

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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 17 points, against 20 points between the best and worst carrier.

5am–8am189 flights90.4%
8am–11am364 flights82.8%
11am–2pm511 flights82.5%
2pm–5pm186 flights77.2%
5pm–8pm255 flights73.5%
8pm–5am263 flights77.9%

Scale runs 65% to 95%.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.4% of the time, against 73.5% for the evening window. That is 17 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 511 flights scheduled in it.

Across the year

Delta on SEA to PHX through the year

Darker means more delays. Figures are on-time percentages.September best, December worst

December is the weak month at 72.2% on time, against 88.7% in September. 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. August was the busiest month here, with 155 flights.

Across the week, Wednesday is the strongest day at 86.6% on time and Monday the weakest at 74.6%, a spread of 12 points.

Arrival by arrival

How late Delta on SEA to PHX runs when it is late

Delta on SEA to PHX often beats the schedule: 499 of 1,741 completed flights, 29%, arrived 15 minutes or more early. The 333 late arrivals split 135 under half an hour, 89 between 30 and 60 minutes, and 109 an hour or more.

15+ min early499 flights28.7%
Within 15 min909 flights52.2%
15–29 min late135 flights7.8%
30–59 min late89 flights5.1%
1–2 hours late65 flights3.7%
2+ hours late44 flights2.5%

Scale runs 0% to 100%.

Share of 1,741 completed flights by arrival against schedule.

58 of 302 late departures made up the time and arrived on time, 19% of them. In the other direction, 89 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at PHX.

The worst days

Worst days for Delta on SEA to PHX

The latest arrival of the period was on 5 January 2026, 11 hours 54 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.

The latest arrivals of Delta on SEA to PHX in the period
Date	Arrived late by	Largest filed cause
5 January 2026	11 hours 54 minutes	Carrier
23 April 2026	10 hours 21 minutes	Carrier
10 March 2026	9 hours 37 minutes	Carrier
6 November 2025	9 hours 8 minutes	Carrier
22 July 2026	8 hours 52 minutes	Carrier

Delay causes

Why Delta runs late on this route

Carrier accounts for 56% of the 22,000 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
56%
Late-arriving aircraft
21%
National Airspace System
20%
Extreme weather
3%
Security
0%

The largest share of delay minutes, 56%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 12,000 of the 22,000 delay minutes reported here. The split is drawn from 22,211 reported delay minutes.

Cancellations sit at 0.96% against a national 1.89%, which is ordinary. Diversions add another 0.57%.

Connections and stage length

What a delay here costs

6.3% of arrivals land an hour or more late, close to the national 8.3%, so 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.

The return leg is a different operation and performs like one: it runs 87.5% on time across 1,767 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 1,768 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. September runs 88.7% 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. 1,741 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures