77% of flights leaving Williston (XWA) arrived on time over the past 12 months, right at the national average of 76%. About 6 flights leave XWA on a typical day; 1.5% were cancelled. 79% 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: 7 a.m. (84% on time). Worst: 3 p.m. (75%).
- Best month: September (86%). Worst: January (68%).
- Most reliable airline here: Delta Air Lines (79%), vs United Airlines at 75%.
- Biggest delay cause: the airlines themselves (58% of delay minutes).
- Year on year: improving (74% → 77%).
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 XWA: when a flight was late, it was under 45 minutes late 41% of the time. About 1 in 10 flights landed an hour or more late, and 1 in 24 three hours or more; 1.5% were cancelled outright.
- On time or early77%
- 15–30 min late5.5%
- 30–60 min late5.3%
- 1–2 hours late4.1%
- 2–3 hours late2.1%
- 3+ hours late4.1%
- Diverted0.6%
- Cancelled1.5%
Share of all 2,347 scheduled flights, past 12 months, by arrival time against schedule.
Best time of day to fly out of XWA
Departure time makes a real difference at XWA. Flights scheduled to leave at 7 a.m. arrived on time 84% of the time; at 3 p.m. it was 75%, a 9-point gap. Taken together, early departures (5–9 a.m.) ran 82% on time against 64% 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. Cancellations cluster too: noon departures were cancelled 2.1% of the time, against 1.5% overall.
Hour × month
Combine the two and the spread is wider still. The most reliable combination at XWA was a 7 a.m. departure in May (93% on time); the least, 3 p.m. in July (62%). 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
January is the hardest month at XWA, with 68% of flights on time across 2023–2026; September is the best at 86%. Summer (June–August) runs 6 points worse than autumn: heavy schedules, peak loads and afternoon thunderstorms. Winter costs 10 points against autumn. Cancellations peak in January (4.5% of flights).
Airlines at XWA
United Airlines runs 57% of departures from XWA, so XWA is effectively its hub. When United Airlines has a bad day, so does the airport. Among airlines with at least 1,000 departures here, Delta Air Lines was the most reliable (79% on time) and United Airlines the least (75%), a 4-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 |
|---|---|---|---|---|---|
| United Airlines | 1,334 | 75% | 79% | 1.3% | −7 min |
| Delta Air Lines | 1,013 | 79% | 79% | 1.8% | −13 min |
Why flights are late at XWA
Airlines report a cause for every flight that arrives 15 or more minutes late. At XWA, 58% of delay minutes came from the airlines themselves: crew, maintenance, cleaning, fueling and baggage. Next is the air traffic system at 16%.
The average taxi from gate to takeoff is 26 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 77% of XWA departures were on time, against 74% in the 12 months before, an improvement of 3 points. The best recent month was May 2026 (89%); the worst, December 2025 (59%).
Last flights of the day
The last flight of the day is a different bet. Across routes from XWA, each airline's final departure was cancelled 1.9% of the time, against 1.3% 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. 3.0% of last flights landed 3+ hours late. The riskiest last flight out was United Airlines to Denver (2.5% cancelled).
| Last flight to | Airline | Leaves | Cancelled | 3h+ late | On time |
|---|---|---|---|---|---|
| DEN Denver | United Airlines | 6:26 p.m. | 2.5% | 3.3% | 65% |
| MSP Minneapolis | Delta Air Lines | 3:37 p.m. | 1.4% | 2.8% | 80% |
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 XWA
- Book the earliest departure you can live with. At XWA the 7 a.m. flights do best.
- Traveling in January? 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 XWA; the one before it leaves you a backup.
- Delayed already? Most delays at XWA come from the airlines themselves. If your inbound plane is late, your flight will be too, whatever the board says.
Routes from XWA
Least reliable first. Routes with at least 365 flights a year.
| To | Flights | On time | Cancelled | Typical arrival |
|---|---|---|---|---|
| DEN Denver | 1,333 | 75% | 1.3% | −7 min |
| MSP Minneapolis | 1,013 | 79% | 1.8% | −13 min |
Flights into XWA
Arriving rather than leaving? These are the routes into Williston Basin, least reliable first. The weakest is from Minneapolis (75% on time).
| From | Flights | On time | Cancelled |
|---|---|---|---|
| MSP Minneapolis | 1,013 | 75% | 1.6% |
| DEN Denver | 1,332 | 76% | 1.5% |
Questions about XWA delays
What is the best time to fly out of XWA?
Flights scheduled at 7 a.m.: over the past year 84% of XWA departures at that hour arrived on time, against 75% at 3 p.m., the worst hour.
What month has the most flight delays at XWA?
January (68% on time). September is the best month (86%).
Which airline is most on time at XWA?
Delta Air Lines: 79% of its XWA departures arrived on time over the past year. United Airlines had the weakest record at 75%.
Why are flights delayed at XWA?
The biggest cause was the airlines themselves (58% of delay minutes): crew, maintenance, cleaning, fueling and baggage. Then the air traffic system (16%).
How often are flights cancelled at XWA?
1.5% of scheduled departures over the past 12 months, peaking in January at 4.5%.
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.