Buffalo (BUF) to Denver (DEN): On-Time Performance
Data through May 2026
When you fly BUF to DEN matters as much as anything else about the booking: the route swung from 93% on-time in September 2024 to just 63% in December 2025. Across the full period the route averages 80% on-time against a national 78%. Morning departures also hold up better than evening ones (87% vs 59%), which matters most in the rough months.
- On-time
- 80%
- arrived <15 min late
- Avg delay
- 13 min
- completed flights
- Cancelled
- 0.3%
- Flights/day
- 1.7
- last 12 months
- Duration
- 3h 38m
- scheduled
- Distance
- 1,359 mi
Best airline from BUF to DEN
3 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 84% | 13 min | 0.3% | 303 |
| Southwest Airlines | 81% | 10 min | 0.2% | 583 |
| Frontier Airlines | 65% | 24 min | 0.7% | 139 |
Monthly on-time trend
Best time to fly from BUF to DEN
Aim for departures around 11 a.m. (95% on-time); avoid 5 p.m. departures (56%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 76% | 17 min |
| Tuesday | 84% | 12 min |
| Wednesday | 84% | 14 min |
| Thursdaybest | 90% | 5 min |
| Friday | 77% | 13 min |
| Saturday | 72% | 16 min |
| Sunday | 82% | 9 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft42%
- Airline operations26%
- National airspace system31%
- Weather2%
Frequently asked questions
- How often are flights from BUF to DEN delayed?
- 20% of BUF–DEN flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 13 minutes.
- Which airline is most reliable from BUF to DEN?
- United Airlines has the best on-time record on this route at 84%, based on 303 flights. 3 airlines flew BUF–DEN frequently enough to compare in this period.
- What is the best time of day to fly from BUF to DEN?
- Departures around 11 a.m. have the best record (95% on-time), while departures around 5 p.m. have the worst (56%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BUF to DEN?
- The scheduled BUF–DEN flight time averages 3h 38m over 1,359 miles. Actual arrival times vary — flights on this route land 15+ minutes late 20% of the time.
- How often are BUF to DEN flights cancelled?
- 0.3% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from BUF to DEN?
- December 2025 was the roughest month in this dataset, with only 63% of arrivals on time. The best was September 2024 at 93%. If your dates are flexible, that 30-point gap is worth planning around.
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Based on 1,025 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.