Carrier route record

OODEN→SEA

SkyWest Airlines · Denver to Seattle

Flights: 220
Period: July 2025 to June 2026
Share of route: 3%
Carriers: 6

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with SkyWest Airlines.

SkyWest on DEN to SEA sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 220 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,903 at 80.0% on time.

United Airlines is the most reliable of the five carriers covered here at 80.0% on time across 1,903 flights.

On time

75.8%

Arrivals under 15 minutes late, of 219 completed flights

Avg delay

70 min

Across delayed arrivals only, not all flights

Cancelled

0.45%

National rate is 1.81%

Whole route

73.9%

Every carrier on DEN to SEA, 6,309 flights

These figures cover 220 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% 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

SkyWest against every carrier on DEN to SEA

SkyWest flew 220 of the 6,309 flights on DEN to SEA, about 3% of it. Its 75.8% on time is 2 points better than the route as a whole, which runs 73.9%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from United at 80.0% to Southwest at 61.7%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 80.0% of the time; Southwest Airlines manages 61.7%. Sample sizes sit next to every figure, because a two-point gap across 1,341 flights means less than a ten-point one.

On-time performance by carrier on DEN to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,903	80.0%	55 min	0.63%	B+
Delta Air Lines	868	79.2%	89 min	0.92%	B+
SkyWest Airlines (this page)thin sample	220	75.8%	70 min	0.45%	B+
Frontier Airlines	419	74.9%	60 min	1.91%	C
Alaska Airlines	1,558	73.8%	57 min	0.96%	C+
Southwest Airlines	1,341	61.7%	47 min	0.30%	D+

The spread between United 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.

Departure window

When SkyWest runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 220 flights.

5am–8am—
8am–11am—
11am–2pm98 flights80.4%
2pm–5pm—
5pm–8pm122 flights72.1%
8pm–5am—

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 80.4% on time, ahead of 5pm–8pm at 72.1%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 5pm–8pm window is the busiest, with 122 flights scheduled in it.

Across the year

SkyWest on DEN to SEA through the year

Jan–Mar 2026172 flights76.6%
Apr–Jun 202648 flights72.9%

Scale runs 65% to 80%. 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 75.8% on time across 220 flights.

Split by quarter, SkyWest on DEN to SEA logged 172 flights in Jan–Mar 2026 and 48 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 75.8% annual figure is the one to use.

Across the week, Saturday is the strongest day at 80.6% on time and Sunday the weakest at 67.7%. 13 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest runs late on this route

One category carries most of the weight here. Carrier accounts for 69% of the 3,713 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.

Carrier
69%
Extreme weather
17%
National Airspace System
14%
Security
1%

Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.7 times the usual weather exposure. The split is drawn from 3,713 reported delay minutes.

The largest share of delay minutes, 69%, 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 2,553 of the 3,713 delay minutes reported here.

Cancellations are rare at 0.45%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.1% 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.

The 1,024 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 85.0% on time across 221 flights, 9 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 9 points of difference.

One caution: this is a thin sample. 220 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 SkyWest on DEN to SEA

Put together: treat all of this as provisional. 220 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 75.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 219 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures