Route reliability record
SEA→CVG
Seattle to Cincinnati
- Flights
- 793
- Period
- September 2025 to August 2026
- Distance
- 1,965 mi
- Carriers
- 2
This route earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 793 SEA to CVG flights, with a median arrival 12 minutes early.
Best time to fly SEA to CVG: a 11am–2pm departure, ideally on a Friday. Flights in that window arrived on time 88.4% of the time and Friday flights 88.9%, against 86.2% for the route overall.
Set against the rest of the country, this route's record is 9 points better than the US average of 77.3%. That gap is worth roughly 89 fewer late arrivals for every thousand flights.
Key figures
On time
86.2%
Arrivals under 15 minutes late, of 780 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
1.13%
National rate is 1.89%
Best carrier
Alaska
83.2% on time across 431 flights
These figures cover 793 flights between September 2025 and August 2026. The median arrival is 12 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 CVG
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 |
|---|---|---|---|---|---|
| Delta Air Linesthin sample | 362 | 89.6% | 59 min | 1.10% | A |
| Alaska Airlines | 431 | 83.2% | 40 min | 1.16% | B |
Flight by flight
Flights on SEA to CVG
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 793 flights.
- 5am–8am—
- 8am–11am249 flights83.7%
- 11am–2pm474 flights88.4%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am70 flights79.7%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 88.4% on time, ahead of 8pm–5am at 79.7%. 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 11am–2pm window is the busiest, with 474 flights scheduled in it.
Explore
Filter SEA to CVG 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 CVG, the best departure window is 11am–2pm at 88.4% on time and the worst is 8pm–5am at 79.7%, a real gap of 8.7 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am—
- 8–11am83.7%
- 11am–2pm88.4%
- 2–5pm—
- 5–8pm—
- 8pm–5am79.7%
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 15 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.
January is the weak month at 76.3% on time, against 91.7% 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. July was the busiest month here, with 92 flights.
Across the week, Friday is the strongest day at 88.9% on time and Sunday the weakest at 75.5%, a spread of 13 points.
Delay causes
Why this route gets delayed
Carrier accounts for 52% of the 4,999 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Carrier
- 28%Late-arriving aircraft
- 19%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 52%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,586 of the 4,999 delay minutes reported here. The split is drawn from 4,999 reported delay minutes.
Cancellations sit at 1.13% against a national 1.89%, which is ordinary. Diversions add another 0.50%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 3.1% 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 1,965 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 77.0% on time across 793 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. 793 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 CVG after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 793 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 86.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 780 completed flights over 12 months sit behind that.
Common questions
SEA to CVG questions
How often is SEA to CVG delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.8% of the 793 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is SEA to CVG compared with the rest of the country?
86.2% of flights arrive on time here against a national 77.3%, a difference of 9 points in its favour. That is worth a A on this site's grading scale.
What time of day has the fewest delays on SEA to CVG?
The 11am–2pm departure window is the strongest at 88.4% on time. The 8pm–5am window is the weakest at 79.7%, 9 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 January delays on SEA to CVG?
January is the weakest month at 76.3% on time, compared with 91.7% in September. Across the year that is 15 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
- CVG to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Cincinnati/Northern Kentucky International (CVG) delay statistics
- Delta Air Lines on SEA to CVG89.6%
- Alaska Airlines on SEA to CVG83.2%
- SEA to LAX, a related route82.0%
- ORD to CVG, a related route72.1%
- SEA to PHX, a related route78.2%
- Delta Air Lines on-time record89.6%
- Alaska Airlines on-time record83.2%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. SEA to CVG and CVG 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.