86% of flights leaving Great Falls (GTF) arrived on time over the past 12 months, 11 points better than the national average of 76%. About 7 flights leave GTF on a typical day; 0.8% were cancelled. 87% 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: 5 a.m. (97% on time). Worst: 2 p.m. (80%).
- Best month: September (90%). Worst: February (79%).
- Biggest delay cause: the airlines themselves (37% of delay minutes).
- Year on year: about the same (86% → 86%).
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 GTF: when a flight was late, it was under 45 minutes late 56% of the time. About 1 in 23 flights landed an hour or more late, and 1 in 89 three hours or more; 0.8% were cancelled outright.
- On time or early86%
- 15–30 min late5.1%
- 30–60 min late3.4%
- 1–2 hours late2.3%
- 2–3 hours late1.0%
- 3+ hours late1.1%
- Diverted0.1%
- Cancelled0.8%
Share of all 2,393 scheduled flights, past 12 months, by arrival time against schedule.
Best time of day to fly out of GTF
Time of day matters more at GTF than almost anything else you control. Flights scheduled to leave at 5 a.m. arrived on time 97% of the time; at 2 p.m. it was 80%, a 17-point gap. Taken together, early departures (5–9 a.m.) ran 94% on time against 83% 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: 1 p.m. departures were cancelled 1.4% of the time, against 0.8% overall.
Hour × month
Combine the two and the spread is wider still. The most reliable combination at GTF was a 5 a.m. departure in May (97% on time); the least, 2 p.m. in February (77%). 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
February is the hardest month at GTF, with 79% of flights on time across 2023–2026; September is the best at 90%. Winter costs 5 points against autumn. Cancellations peak in March (1.2% of flights).
Airlines at GTF
Delta Air Lines runs 45% of departures from GTF.
| Airline | Departures | On time | Left on time | Cancelled | Typical arrival |
|---|---|---|---|---|---|
| Delta Air Lines | 1,079 | 92% | 93% | 0.7% | −14 min |
| United Airlines | 750 | 85% | 86% | 0.8% | −16 min |
| Alaska Airlines | 364 | 76% | 77% | 0.8% | −3 min |
| Allegiant Air | 200 | 80% | 80% | 0.5% | −6 min |
Why flights are late at GTF
Airlines report a cause for every flight that arrives 15 or more minutes late. At GTF, 37% of delay minutes came from the airlines themselves: crew, maintenance, cleaning, fueling and baggage. Next is late-arriving aircraft at 30%.
The average taxi from gate to takeoff is 15 minutes, shorter than at most large U.S. airports.
Month by month
Over the latest 12 months 86% of GTF departures were on time, against 86% in the 12 months before: essentially unchanged. The best recent month was January 2026 (92%); the worst, August 2026 (79%).
Last flights of the day
The last flight of the day is a different bet. Across routes from GTF, each airline's final departure was cancelled 0.7% of the time, against 0.8% for its earlier flights, about the same. 1.5% of last flights landed 3+ hours late. The riskiest last flight out was United Airlines to Denver (0.8% cancelled).
| Last flight to | Airline | Leaves | Cancelled | 3h+ late | On time |
|---|---|---|---|---|---|
| DEN Denver | United Airlines | 2:37 p.m. | 0.8% | 2.5% | 80% |
| SLC Salt Lake City | Delta Air Lines | 6:25 p.m. | 0.5% | 0.5% | 88% |
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 GTF
- Book the earliest departure you can live with. At GTF the 5 a.m. flights do best.
- Traveling in February? Leave extra slack for anything that can't move: cruises, weddings, the last connection of the day.
- Delayed already? Most delays at GTF come from the airlines themselves. If your inbound plane is late, your flight will be too, whatever the board says.
Routes from GTF
Least reliable first. Routes with at least 365 flights a year.
| To | Flights | On time | Cancelled | Typical arrival |
|---|---|---|---|---|
| DEN Denver | 728 | 85% | 0.8% | −16 min |
| SLC Salt Lake City | 1,072 | 92% | 0.8% | −14 min |
Flights into GTF
Arriving rather than leaving? These are the routes into Great Falls, least reliable first. The weakest is from Denver (77% on time).
| From | Flights | On time | Cancelled |
|---|---|---|---|
| DEN Denver | 728 | 77% | 0.5% |
| SLC Salt Lake City | 1,072 | 93% | 0.8% |
Questions about GTF delays
What is the best time to fly out of GTF?
Flights scheduled at 5 a.m.: over the past year 97% of GTF departures at that hour arrived on time, against 80% at 2 p.m., the worst hour.
What month has the most flight delays at GTF?
February (79% on time). September is the best month (90%).
Why are flights delayed at GTF?
The biggest cause was the airlines themselves (37% of delay minutes): crew, maintenance, cleaning, fueling and baggage. Then late-arriving aircraft (30%).
How often are flights cancelled at GTF?
0.8% of scheduled departures over the past 12 months, peaking in March at 1.2%.
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.