Route reliability record
CVG→SEA
Cincinnati to Seattle
- Flights
- 793
- Period
- July 2025 to June 2026
- Distance
- 1,965 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land roughly 55 minutes behind schedule. That rests on 793 CVG to SEA flights, with a median arrival 3 minutes early.
Best time to fly CVG to SEA: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 84.3% of the time and Wednesday flights 84.8%, against 74.4% for the route overall.
The US average over the same twelve months is 77.6%, 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
74.4%
Arrivals under 15 minutes late, of 784 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
1.13%
National rate is 1.81%
Best carrier
Alaska
65.6% on time across 431 flights
These figures cover 793 flights between July 2025 and June 2026. The median arrival is 3 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.
Carrier by carrier
Which airline is most reliable on CVG to SEA
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 | 84.7% | 50 min | 0.55% | B+ |
| Alaska Airlines | 431 | 65.6% | 54 min | 1.62% | C |
Flight by flight
Flights on CVG to SEA
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.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 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–8am383 flights84.3%
- 8am–11am119 flights57.4%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm291 flights68.1%
- 8pm–5am—
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 84.3% of the time, against 57.4% for the morning window. That is 27 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 383 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 56 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.
December is the weak month at 39.0% on time, against 95.0% 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, Wednesday is the strongest day at 84.8% on time and Thursday the weakest at 68.2%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 11,000 reported delay minutes.
- 36%National Airspace System
- 34%Carrier
- 25%Late-arriving aircraft
- 5%Extreme weather
- 0%Security
36% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,847 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 10,645 reported delay minutes.
Cancellations sit at 1.13% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
5.9% 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 roughly 55 minutes, which a normal layover absorbs.
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 81.7% on time across 793 flights, 7 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 7 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 SEA 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 74.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 784 completed flights over 12 months sit behind that.
Common questions
CVG to SEA questions
How often is CVG to SEA delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.6% of the 793 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 55 minutes on average.
How reliable is CVG to SEA compared with the rest of the country?
74.4% of flights arrive on time here against a national 77.6%, a difference of 3 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on CVG to SEA?
The 5am–8am departure window is the strongest at 84.3% on time. The 8am–11am window is the weakest at 57.4%, 27 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 December delays on CVG to SEA?
December is the weakest month at 39.0% on time, compared with 95.0% in September. Across the year that is 56 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
- SEA to CVG — the return legseparate record
- Cincinnati/Northern Kentucky International (CVG) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on CVG to SEA84.7%
- Alaska Airlines on CVG to SEA65.6%
- CVG to ORD, a related route70.2%
- LAX to SEA, a related route85.4%
- CVG to ATL, a related route86.4%
- Delta Air Lines on-time record84.7%
- Alaska Airlines on-time record65.6%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. CVG to SEA and SEA to CVG 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.