Route reliability record
OAK→DEN
Oakland to Denver
- Flights
- 1,607
- Period
- July 2025 to June 2026
- Distance
- 957 mi
- Carriers
- 1
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, 5 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 1,607 OAK to DEN flights, with a median arrival 1 minute late.
Best time to fly OAK to DEN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 93.1% of the time and Saturday flights 77.6%, against 73.0% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 46 extra late arrivals.
Key figures
On time
73.0%
Arrivals under 15 minutes late, of 1,592 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.44%
National rate is 1.81%
Best carrier
Southwest
73.0% on time across 1,607 flights
These figures cover 1,607 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
Which airline is most reliable on OAK to DEN
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 1,607 | 73.0% | 47 min | 0.44% | C+ |
Best ways to make this trip
The most reliable ways to fly Oakland to Denver
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SJC → DENSan Jose to Denver | United Airlines | 87.9% | 88.3% | 0.40% | 8am–11am, Sun | — |
| 2. SFO → DENSan Francisco to Denver | United Airlines | 82.0% | 82.2% | 0.27% | 5am–8am, Sun | UA 2348 08:35 |
| 3. SJC → DENSan Jose to Denver | Southwest Airlines | 75.9% | 76.3% | 0.46% | 5am–8am, Sat | — |
| 4. OAK → DENOakland to Denver | Southwest Airlines | 72.7% | 73.0% | 0.44% | 5am–8am, Sat | — |
| 5. SFO → DENSan Francisco to Denver | Frontier Airlines | 72.5% | 73.2% | 0.99% | 8am–11am, Sat | F9 1230 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 43 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–8am379 flights93.1%
- 8am–11am309 flights89.6%
- 11am–2pm317 flights63.1%
- 2pm–5pm290 flights50.5%
- 5pm–8pm209 flights60.4%
- 8pm–5am103 flights67.6%
Scale runs 40% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 50.5% for the afternoon window. That is 43 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 379 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 25 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.
June is the worst month at 62.8% on time, 25 points below January, the best at 87.6%. 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. July was the busiest month here, with 159 flights.
Across the week, Saturday is the strongest day at 77.6% on time and Friday the weakest at 67.5%. 10 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 20,000 reported delay minutes.
- 41%Late-arriving aircraft
- 30%Carrier
- 25%National Airspace System
- 4%Extreme weather
- 0%Security
41% 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 20,000 reported delay minutes here, that single category outweighs weather by 10 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 20,291 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 93.1% on time here.
Cancellations are rare at 0.44%, 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 actually costs
6.0% 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 45 minutes, which a normal layover absorbs.
The 957 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 65.1% on time across 1,610 flights, 8 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 8 points of difference.
The sample behind these figures is 1,607 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 87.6% on time and June 62.8%, a swing of 25 points. If the dates move at all, move them out of June before you think about anything else. 1,592 completed flights over 12 months sit behind that.
Common questions
OAK to DEN questions
How often is OAK to DEN 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 27.0% of the 1,607 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is OAK to DEN compared with the rest of the country?
73.0% of flights arrive on time here against a national 77.6%, a difference of 5 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on OAK to DEN?
The 5am–8am departure window is the strongest at 93.1% on time. The 2pm–5pm window is the weakest at 50.5%, 43 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 June delays on OAK to DEN?
June is the weakest month at 62.8% on time, compared with 87.6% in January. Across the year that is 25 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
- DEN to OAK — the return legseparate record
- Oakland International (OAK) delay statistics
- Denver International (DEN) delay statistics
- OAK to LAS, a related route78.1%
- PHX to DEN, a related route77.2%
- OAK to SAN, a related route66.9%
- Southwest Airlines on-time record73.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. OAK to DEN and DEN to OAK 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.