BUF to DEN flight delays & on-time performance
Nonstop flights from Buffalo Niagara International Airport to Denver International Airport · 1,359 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at BUF or DEN right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Buffalo (BUF) to Denver (DEN) arrived on time 75% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 0.2% were cancelled, and 7% arrived an hour or more late.
- United Airlines was the most punctual airline here (84% on time); Frontier Airlines was the least (63%).
- Departures scheduled around 7am did best (89% on time); around 4pm did worst (34%).
- Thursday was the most reliable day to fly (82% on time) and Saturday the least (70%).
- The largest source of delay minutes was late-arriving aircraft (36%).
Which airline is most on time from BUF to DEN?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| United Airlines | 84% | 0.0% | 13 min | 5.1% | 293 |
| Southwest Airlines | 66% | 0.4% | 18 min | 8.6% | 258 |
| Frontier Airlines | 63% | 0.0% | 17 min | 8.6% | 35 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am86%28 flights
- 7am89%38 flights
- 8am84%236 flights
- 9am85%71 flights
- 10am80%52 flights
- 12pm78%27 flights
- 3pm40%10 flights
- 4pm34%71 flights
- 5pm52%27 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday76%1.1% cancelled
- Tuesday73%0.0% cancelled
- Wednesday71%0.0% cancelled
- Thursday82%0.0% cancelled
- Friday74%0.0% cancelled
- Saturday70%0.0% cancelled
- Sunday80%0.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft36%
- Airline (crew, maintenance, cleaning, fueling)36%
- Air traffic control & airport congestion26%
- Extreme weather3%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather100%
- Airline (crew, maintenance, cleaning, fueling)0%
- Air traffic control & airport congestion0%
- Security0%
BUF to DEN: common questions
- How often are BUF to DEN flights on time?
- 75% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Buffalo to Denver cancelled?
- 0.2% of scheduled flights were cancelled (1 of 586).
- How long are typical delays?
- Across all flights the average arrival delay was 15 min (early arrivals count as zero). Flights that were late arrived 57 min behind schedule on average, and 6.8% of flights were an hour or more late.
- How long is taxi time at BUF?
- Flights on this route spent 14 min taxiing from the gate to takeoff on average.
Related routes
Return trip: DEN to BUF — 68% on time
More flights from Buffalo
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: BUF → DEN, nonstop flights by US airlines that report to the DOT. How we calculate this.