Route reliability record
DEN→BIS
Denver to Bismarck
- Flights
- 1,502
- Period
- July 2025 to June 2026
- Distance
- 516 mi
- Carriers
- 1
This route lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 1,502 DEN to BIS flights, with a median arrival 7 minutes early.
Best time to fly DEN to BIS: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 84.6% of the time and Wednesday flights 84.9%, against 76.2% 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
76.2%
Arrivals under 15 minutes late, of 1,486 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.81%
Best carrier
SkyWest
76.2% on time across 1,502 flights
These figures cover 1,502 flights between July 2025 and June 2026. Beyond the headline rate, 10.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on DEN to BIS
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,502 | 76.2% | 88 min | 0.73% | B+ |
Flight by flight
Flights on DEN to BIS
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 20 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–8am79 flights84.6%
- 8am–11am363 flights83.3%
- 11am–2pm278 flights81.4%
- 2pm–5pm86 flights76.5%
- 5pm–8pm364 flights64.8%
- 8pm–5am332 flights74.7%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.8% on time, against 84.6% 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 5pm–8pm window is the busiest, with 364 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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.
August is the worst month at 64.9% on time, 27 points below November, the best at 92.0%. 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 154 flights.
Across the week, Wednesday is the strongest day at 84.9% on time and Monday the weakest at 69.7%. 15 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 31,000 reported delay minutes.
- 42%Carrier
- 33%Late-arriving aircraft
- 19%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 13,000 of the 31,000 delay minutes reported here. The split is drawn from 31,093 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 84.6% on time here.
Cancellations are rare at 0.73%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 516 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 runs 78.9% on time across 1,502 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,502 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 BIS 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. November runs 92.0% on time and August 64.9%, a swing of 27 points. If the dates move at all, move them out of August before you think about anything else. 1,486 completed flights over 12 months sit behind that.
Common questions
DEN to BIS questions
How often is DEN to BIS 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 23.8% of the 1,502 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is DEN to BIS compared with the rest of the country?
76.2% of flights arrive on time here against a national 77.6%, a difference of about a point against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DEN to BIS?
The 5am–8am departure window is the strongest at 84.6% on time. The 5pm–8pm window is the weakest at 64.8%, 20 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 August delays on DEN to BIS?
August is the weakest month at 64.9% on time, compared with 92.0% in November. Across the year that is 27 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
- BIS to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- DEN to PHX, a related route75.7%
- MSP to BIS, a related route80.7%
- DEN to SLC, a related route77.5%
- SkyWest Airlines on-time record76.2%
- 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. DEN to BIS and BIS to DEN 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.