Route reliability record
SEA→TPA
Seattle to Tampa
- Flights
- 975
- Period
- September 2025 to August 2026
- Distance
- 2,520 mi
- Carriers
- 2
This route lands a B+, 3 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 roughly 50 minutes on average. That rests on 975 SEA to TPA flights, with a median arrival 7 minutes early.
Best time to fly SEA to TPA: a 8pm–5am departure, ideally on a Saturday. Flights in that window arrived on time 81.9% of the time and Saturday flights 86.3%, against 80.4% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.4%
Arrivals under 15 minutes late, of 962 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.51%
National rate is 1.89%
Best carrier
Alaska
81.3% on time across 612 flights
These figures cover 975 flights between September 2025 and August 2026. The median arrival is 7 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
Which airline is most reliable on SEA to TPA
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 612 | 81.3% | 48 min | 0.49% | B+ |
| Delta Air Linesthin sample | 363 | 78.7% | 57 min | 0.55% | B+ |
Flight by flight
Flights on SEA to TPA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
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 975 flights.
- 5am–8am—
- 8am–11am365 flights80.7%
- 11am–2pm362 flights78.9%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am248 flights81.9%
Scale runs 70% to 85%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 81.9% on time across 248 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Explore
Filter SEA to TPA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SEA to TPA, the best departure window is 8pm–5am at 81.9% on time and the worst is 11am–2pm at 78.9%, a narrow gap of 3.0 points. All US flights leaving 8pm–5am ran 70.1%.
- 5–8am—
- 8–11am80.7%
- 11am–2pm78.9%
- 2–5pm—
- 5–8pm—
- 8pm–5am81.9%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 21 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 69.2% on time, 21 points below February, the best at 90.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. May was the busiest month here, with 92 flights.
Across the week, Saturday is the strongest day at 86.3% on time and Sunday the weakest at 72.7%, a spread of 14 points.
Delay causes
Why this route gets delayed
Carrier accounts for 49% of the 9,726 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Carrier
- 26%National Airspace System
- 17%Late-arriving aircraft
- 8%Extreme weather
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,791 of the 9,726 delay minutes reported here. The split is drawn from 9,726 reported delay minutes.
Cancellations are rare at 0.51%, below the national 1.89% 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 actually costs
Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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 74.2% on time across 975 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 975 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.
Work out the risk of missing a connection in TPA after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 975 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 80.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 962 completed flights over 12 months sit behind that.
Common questions
SEA to TPA questions
How often is SEA to TPA delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.6% of the 975 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is SEA to TPA compared with the rest of the country?
80.4% of flights arrive on time here against a national 77.3%, a difference of 3 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on SEA to TPA?
The 8pm–5am departure window is the strongest at 81.9% on time. The 11am–2pm window is the weakest at 78.9%, 3 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on SEA to TPA?
July is the weakest month at 69.2% on time, compared with 90.4% in February. Across the year that is 21 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- TPA to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Tampa International (TPA) delay statistics
- Alaska Airlines on SEA to TPA81.3%
- Delta Air Lines on SEA to TPA78.7%
- SEA to LAX, a related route82.0%
- ATL to TPA, a related route73.0%
- SEA to PHX, a related route78.2%
- Alaska Airlines on-time record81.3%
- Delta Air Lines on-time record78.7%
- Worst months to fly in the US, ranked by the data
- How to read this site: grades, sample sizes, and honest caveats
Direction matters. SEA to TPA and TPA to SEA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.