80% of flights leaving Bismarck (BIS) arrived on time over the past 12 months, 4 points better than the national average of 76%. About 12 flights leave BIS on a typical day; 0.8% were cancelled. 81% pushed back from the gate on time, so most of the lateness is already there when the flight leaves the gate.
At a glance
- Best hour to fly: 6 a.m. (87% on time). Worst: 2 p.m. (75%).
- Best month: October (87%). Worst: December (73%).
- Most reliable airline here: Delta Air Lines (82%), vs United Airlines at 79%.
- Biggest delay cause: the airlines themselves (44% of delay minutes).
- Year on year: improving (78% → 80%).
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for flights leaving BIS: when a flight was late, it was under 45 minutes late 46% of the time. About 1 in 12 flights landed an hour or more late, and 1 in 44 three hours or more; 0.8% were cancelled outright.
- On time or early80%
- 15–30 min late5.5%
- 30–60 min late5.4%
- 1–2 hours late4.4%
- 2–3 hours late1.6%
- 3+ hours late2.3%
- Diverted0.4%
- Cancelled0.8%
Share of all 4,555 scheduled flights, past 12 months, by arrival time against schedule.
Best time of day to fly out of BIS
Departure time makes a real difference at BIS. Flights scheduled to leave at 6 a.m. arrived on time 87% of the time; at 2 p.m. it was 75%, a 12-point gap. Taken together, early departures (5–9 a.m.) ran 85% on time against 73% for the evening bank (5–10 p.m.). Early planes usually start the day at the airport, so they haven't had a chance to pick up delays elsewhere. By evening a late inbound aircraft, a crew running out of duty hours or an afternoon thunderstorm can push one late flight into the next.
Hour × month
Combine the two and the spread is wider still. The most reliable combination at BIS was a 5 a.m. departure in October (94% on time); the least, 5 p.m. in June (59%). If you can only move one thing, move the hour. Departure hour usually shifts the odds more than the month does.
Each cell: on-time rate for that departure hour in that calendar month, 2023–2026. Find your travel month, then look along the row for the greenest hour.
Best and worst months
December is the hardest month at BIS, with 73% of flights on time across 2023–2026; October is the best at 87%. Summer (June–August) runs 7 points worse than autumn: heavy schedules, peak loads and afternoon thunderstorms. Winter costs 10 points against autumn. Cancellations peak in January (1.8% of flights).
Airlines at BIS
Delta Air Lines runs 38% of departures from BIS. Among airlines with at least 1,000 departures here, Delta Air Lines was the most reliable (82% on time) and United Airlines the least (79%), a 3-point difference. On a route where both fly, that difference is worth more than a small fare gap.
| Airline | Departures | On time | Left on time | Cancelled | Typical arrival |
|---|---|---|---|---|---|
| Delta Air Lines | 1,746 | 82% | 83% | 0.8% | −14 min |
| United Airlines | 1,433 | 79% | 81% | 0.7% | −12 min |
| American Airlines | 1,002 | 79% | 80% | 0.9% | −12 min |
| Allegiant Air | 374 | 70% | 76% | 1.1% | −6 min |
Why flights are late at BIS
Airlines report a cause for every flight that arrives 15 or more minutes late. At BIS, 44% of delay minutes came from the airlines themselves: crew, maintenance, cleaning, fueling and baggage. Next is late-arriving aircraft at 31%.
The average taxi from gate to takeoff is 20 minutes, longer than at most large U.S. airports. Airlines pad schedules for it, but a long queue on a busy afternoon still eats into the buffer.
Month by month
Over the latest 12 months 80% of BIS departures were on time, against 78% in the 12 months before, an improvement of 2 points. The best recent month was October 2025 (87%); the worst, December 2025 (62%).
Worst cancellation days
The worst single day in the past year was Sunday, Mar 15, 2026, when 38% of 13 scheduled departures were cancelled. Days like that are usually a major storm, a system outage or a holiday peak hitting bad weather. No average predicts them, so on a stormy forecast, check your airline's travel waivers.
| Date | Departures | Cancelled | On time |
|---|---|---|---|
| Mar 15, 2026 | 13 | 38% | 46% |
| Nov 11, 2025 | 12 | 25% | 67% |
| Jan 24, 2026 | 10 | 20% | 70% |
| Jan 26, 2026 | 12 | 17% | 50% |
| Feb 17, 2026 | 12 | 17% | 50% |
| Dec 7, 2025 | 14 | 14% | 29% |
| Dec 25, 2025 | 11 | 9% | 45% |
| Jan 16, 2026 | 11 | 9% | 27% |
| Nov 8, 2025 | 11 | 9% | 55% |
| Apr 3, 2026 | 12 | 8% | 58% |
Last flights of the day
The last flight of the day is a different bet. Across routes from BIS, each airline's final departure was cancelled 1.1% of the time, against 0.7% for its earlier flights (1.5× as often). Late in the day crews run short on duty hours, aircraft arrive late from elsewhere, and with no later flight to fold passengers into, cancelling is easier for the airline. 2.2% of last flights landed 3+ hours late. The riskiest last flight out was United Airlines to Denver (1.1% cancelled).
| Last flight to | Airline | Leaves | Cancelled | 3h+ late | On time |
|---|---|---|---|---|---|
| DEN Denver | United Airlines | 6:25 p.m. | 1.1% | 3.6% | 64% |
| DFW Dallas | American Airlines | 1:55 p.m. | 0.8% | 1.7% | 77% |
| MSP Minneapolis | Delta Air Lines | 5:40 p.m. | 1.4% | 1.1% | 84% |
Each airline's last scheduled departure of the day on a route, on days it flies the route at least twice; past 12 months. Riskiest first.
Tips for flying out of BIS
- Book the earliest departure you can live with. At BIS the 6 a.m. flights do best.
- Traveling in December? Leave extra slack for anything that can't move: cruises, weddings, the last connection of the day.
- Choosing between airlines? Delta Air Lines has the better record here.
- Need to arrive tonight? Don't book the last flight out of BIS; the one before it leaves you a backup.
- Delayed already? Most delays at BIS come from the airlines themselves. If your inbound plane is late, your flight will be too, whatever the board says.
Routes from BIS
Where you're going matters too. From BIS, the most reliable busy route was to Minneapolis (MSP, 82% on time) and the least reliable to Denver (DEN, 79%). Flights into congested airports inherit their delays: an air traffic program at the destination holds planes on the ground here.
Least reliable first. Routes with at least 365 flights a year.
| To | Flights | On time | Cancelled | Typical arrival |
|---|---|---|---|---|
| DEN Denver | 1,433 | 79% | 0.7% | −12 min |
| DFW Dallas | 728 | 81% | 1.1% | −12 min |
| MSP Minneapolis | 1,746 | 82% | 0.8% | −14 min |
Flights into BIS
Arriving rather than leaving? These are the routes into Bismarck, least reliable first. The weakest is from Denver (76% on time).
| From | Flights | On time | Cancelled |
|---|---|---|---|
| DEN Denver | 1,433 | 76% | 0.7% |
| DFW Dallas | 728 | 79% | 1.1% |
| MSP Minneapolis | 1,746 | 80% | 1.0% |
Questions about BIS delays
What is the best time to fly out of BIS?
Flights scheduled at 6 a.m.: over the past year 87% of BIS departures at that hour arrived on time, against 75% at 2 p.m., the worst hour.
What month has the most flight delays at BIS?
December (73% on time). October is the best month (87%).
Which airline is most on time at BIS?
Delta Air Lines: 82% of its BIS departures arrived on time over the past year. United Airlines had the weakest record at 79%.
Why are flights delayed at BIS?
The biggest cause was the airlines themselves (44% of delay minutes): crew, maintenance, cleaning, fueling and baggage. Then late-arriving aircraft (31%).
How often are flights cancelled at BIS?
0.8% of scheduled departures over the past 12 months, peaking in January at 1.8%.
Hours are scheduled local departure times. "On time" means arriving less than 15 minutes late at the destination; cancelled and diverted flights count as not on time. Method.