Route reliability record
BIS→DEN
Bismarck to Denver
- Flights
- 1,433
- Period
- September 2025 to August 2026
- Distance
- 516 mi
- Carriers
- 1
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 close to two hours on average. That rests on 1,433 BIS to DEN flights, with a median arrival 12 minutes early.
Best time to fly BIS to DEN: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 88.9% of the time and Wednesday flights 83.7%, against 79.9% 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
79.9%
Arrivals under 15 minutes late, of 1,415 completed flights
Avg delay
107 min
Across delayed arrivals only, not all flights
Cancelled
0.70%
National rate is 1.89%
Best carrier
SkyWest
79.9% on time across 1,433 flights
These figures cover 1,433 flights between September 2025 and August 2026. Beyond the headline rate, 9.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on BIS 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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,433 | 79.9% | 107 min | 0.70% | B+ |
Flight by flight
Flights on BIS to DEN
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 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.
- 5am–8am362 flights88.9%
- 8am–11am364 flights79.5%
- 11am–2pm256 flights85.7%
- 2pm–5pm127 flights88.9%
- 5pm–8pm322 flights61.9%
- 8pm–5am2 flights—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.9% on time, against 88.9% 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 8am–11am window is the busiest, with 364 flights scheduled in it.
Explore
Filter BIS to DEN 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 BIS to DEN, the best departure window is 5am–8am at 88.9% on time and the worst is 5pm–8pm at 61.9%, a wide gap of 27.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am88.9%
- 8–11am79.5%
- 11am–2pm85.7%
- 2–5pm88.9%
- 5–8pm61.9%
- 8pm–5am—
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 22 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 66.9% on time, against 89.3% in November. 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. September was the busiest month here, with 137 flights.
Across the week, Wednesday is the strongest day at 83.7% on time and Monday the weakest at 74.6%, a spread of 9 points.
Delay causes
Why this route gets delayed
Carrier accounts for 54% of the 30,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 24%Late-arriving aircraft
- 18%National Airspace System
- 4%Extreme weather
- 1%Security
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 16,000 of the 30,000 delay minutes reported here. The split is drawn from 30,438 reported delay minutes.
Cancellations are rare at 0.70%, 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
9.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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.
The return leg is a different operation and performs like one: it runs 76.9% on time across 1,433 flights, 3 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 3 points of difference.
The sample behind these figures is 1,433 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. November runs 89.3% on time and December 66.9%, a swing of 22 points. If the dates move at all, move them out of December before you think about anything else. 1,415 completed flights over 12 months sit behind that.
Common questions
BIS to DEN questions
How often is BIS to DEN 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 20.1% of the 1,433 flights in this analysis, against 22.7% nationally. Delayed flights are late by close to two hours on average.
How reliable is BIS to DEN compared with the rest of the country?
79.9% 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 BIS to DEN?
The 5am–8am departure window is the strongest at 88.9% on time. The 5pm–8pm window is the weakest at 61.9%, 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 BIS to DEN?
December is the weakest month at 66.9% on time, compared with 89.3% in November. Across the year that is 22 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 BIS — the return legseparate record
- Denver International (DEN) delay statistics
- BIS to MSP, a related route84.7%
- PHX to DEN, a related route76.7%
- BIS to DFW, a related route82.4%
- SkyWest Airlines on-time record79.9%
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
Direction matters. BIS to DEN and DEN to BIS 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.