Carrier route record

ASTPA→SEA

Alaska Airlines · Tampa to Seattle

Flights: 613
Period: July 2025 to June 2026
Share of route: 63%
Carriers: 2

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

Alaska on TPA to SEA sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 10 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 613 flights, with a median arrival 4 minutes late.

The national on-time rate over the same period is 77.6%, so Alaska on TPA to SEA runs 10 points behind the country as a whole. Across a thousand flights that is about 96 extra late arrivals.

On time

68.0%

Arrivals under 15 minutes late, of 603 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

0.82%

National rate is 1.81%

Whole route

74.9%

Every carrier on TPA to SEA, 976 flights

These figures cover 613 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Alaska against every carrier on TPA to SEA

Alaska flew 613 of the 976 flights on TPA to SEA, most of the route. Its 68.0% on time is 7 points worse than the route as a whole, which runs 74.9%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 86.6% to Alaska at 68.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on TPA to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Linesthin sample	363	86.6%	68 min	0.83%	A+
Alaska Airlines (this page)	613	68.0%	50 min	0.82%	C+

Flight by flight

Alaska flight numbers on TPA to SEA

AS 32618:5558.0% · 275 flights

Departure window

When Alaska runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am310 flights75.2%
8am–11am—
11am–2pm—
2pm–5pm—
5pm–8pm303 flights60.5%
8pm–5am—

Scale runs 50% to 80%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.5% on time, against 75.2% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 310 flights scheduled in it.

Across the year

Alaska on TPA to SEA through the year

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

December is the weak month at 51.9% on time, against 84.2% in November. 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. May was the busiest month here, with 62 flights.

Across the week, Tuesday is the strongest day at 75.9% on time and Thursday the weakest at 61.1%. 15 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Alaska runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,703 reported delay minutes.

Late-arriving aircraft
35%
National Airspace System
29%
Carrier
29%
Extreme weather
6%
Security
1%

35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 9,703 reported delay minutes here, that single category outweighs weather by 6 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 9,703 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 75.2% on time here.

Cancellations are rare at 0.82%, 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

7.3% 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 50 minutes, which a normal layover absorbs.

At 2,520 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg is a different operation and performs like one: it runs 79.9% on time across 613 flights, 12 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 12 points of difference.

One caution: this is a thin sample. 613 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 Alaska on TPA to SEA

Put together: treat all of this as provisional. 613 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 68.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 603 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