Carrier route record

F9PHX→SEA

Frontier Airlines · Phoenix to Seattle

Flights: 116
Period: September 2025 to August 2026
Share of route: 2%
Carriers: 7

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

Frontier on PHX to SEA lands a B+, 6 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 an hour and a half on average. That rests on 116 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 761 at 87.6% on time.

Envoy Air is the most reliable of the five carriers covered here at 87.6% on time across 761 flights.

On time

83.6%

Arrivals under 15 minutes late, of 116 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.89%

Whole route

82.2%

Every carrier on PHX to SEA, 7,202 flights

These figures cover 116 flights between September 2025 and August 2026. Beyond the headline rate, 9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

Frontier against every carrier on PHX to SEA

Frontier flew 116 of the 7,202 flights on PHX to SEA, about 2% of it. Its 83.6% on time is about level with the route as a whole at 82.2%. Ranked by on-time rate it is number four of seven carriers on the route, where the range runs from Envoy at 87.6% to Southwest at 62.2%. One 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 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.

On-time performance by carrier on PHX to SEA
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 Airlines (this page)thin 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.

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Departure window

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 25 points between the best and worst carrier.

5am–8am42 flights95.2%
8am–11am5 flights—
11am–2pm2 flights—
2pm–5pm33 flights81.8%
5pm–8pm34 flights70.6%
8pm–5am—

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.2% of the time, against 70.6% for the evening window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 42 flights scheduled in it.

Across the year

Frontier on PHX to SEA through the year

Jul–Sep 202517 flights—
Oct–Dec 202542 flights81.0%
Jan–Mar 202647 flights80.9%
Apr–Jun 202610 flights—

Scale runs 70% to 85%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 83.6% on time across 116 flights.

Split by quarter, Frontier on PHX to SEA logged 17 flights in Jul–Sep 2025, 42 flights in Oct–Dec 2025, 47 flights in Jan–Mar 2026 and 10 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 83.6% annual figure is the one to use.

Arrival by arrival

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

Frontier on PHX to SEA often beats the schedule: 40 of 116 completed flights, 34%, arrived 15 minutes or more early. When Frontier on PHX to SEA is late it tends to be very late: 11 of its 19 late arrivals were an hour or more behind, and 4 were two hours or more.

15+ min early40 flights34.5%
Within 15 min57 flights49.1%
15–29 min late2 flights1.7%
30–59 min late6 flights5.2%
1–2 hours late7 flights6.0%
2+ hours late4 flights3.4%

Scale runs 0% to 100%.

Share of 116 completed flights by arrival against schedule.

Only 19 of 116 completed flights left 15 minutes late or more, too few to say how often the time is made up.

The worst days

Worst days for Frontier on PHX to SEA

The latest arrival of the period was on 10 November 2025, 2 hours 40 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across November, October, March and September, with no single month standing out.

The latest arrivals of Frontier on PHX to SEA in the period
Date	Arrived late by	Largest filed cause
10 November 2025	2 hours 40 minutes	Carrier
10 October 2025	2 hours 36 minutes	Late-arriving aircraft
25 November 2025	2 hours 27 minutes	Carrier
11 March 2026	2 hours 17 minutes	National Airspace System
1 September 2025	1 hour 51 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 44% of the 1,577 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
44%
Carrier
32%
National Airspace System
24%

44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,577 reported delay minutes here, that single category outweighs weather by 44 to one. The split is drawn from 1,577 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 95.2% on time here.

Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.

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 74.5% on time across 116 flights, 9 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 9 points of difference.

One caution: this is a thin sample. 116 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 Frontier on PHX to SEA

Put together: treat all of this as provisional. 116 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 83.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 116 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