DEN to BUF flight delays & on-time performance
Nonstop flights from Denver International Airport to Buffalo Niagara International Airport · 1,359 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at DEN or BUF right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Denver (DEN) to Buffalo (BUF) arrived on time 68% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 0.2% were cancelled, and 11% arrived an hour or more late.
- Frontier Airlines was the most punctual airline here (83% on time); Southwest Airlines was the least (61%).
- Departures scheduled around 9am did best (88% on time); around 7pm did worst (37%).
- Wednesday was the most reliable day to fly (74% on time) and Monday the least (64%).
- The largest source of delay minutes was late-arriving aircraft (50%).
Which airline is most on time from DEN to BUF?
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 |
|---|---|---|---|---|---|
| Frontier Airlines | 83% | 0.0% | 9 min | 2.9% | 35 |
| United Airlines | 72% | 0.0% | 24 min | 14.6% | 294 |
| Southwest Airlines | 61% | 0.4% | 19 min | 7.4% | 258 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 9am88%25 flights
- 10am85%34 flights
- 11am76%50 flights
- 12pm54%41 flights
- 1pm59%17 flights
- 4pm64%15 flights
- 5pm68%346 flights
- 7pm37%27 flights
- 8pm54%13 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday64%0.0% cancelled
- Tuesday71%1.5% cancelled
- Wednesday74%0.0% cancelled
- Thursday67%0.0% cancelled
- Friday70%0.0% cancelled
- Saturday65%0.0% cancelled
- Sunday66%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 aircraft50%
- Airline (crew, maintenance, cleaning, fueling)29%
- Air traffic control & airport congestion17%
- Extreme weather4%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather100%
- Airline (crew, maintenance, cleaning, fueling)0%
- Air traffic control & airport congestion0%
- Security0%
DEN to BUF: common questions
- How often are DEN to BUF flights on time?
- 68% 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 Denver to Buffalo cancelled?
- 0.2% of scheduled flights were cancelled (1 of 587).
- How long are typical delays?
- Across all flights the average arrival delay was 21 min (early arrivals count as zero). Flights that were late arrived 61 min behind schedule on average, and 10.8% of flights were an hour or more late.
- How long is taxi time at DEN?
- Flights on this route spent 21 min taxiing from the gate to takeoff on average.
Related routes
Return trip: BUF to DEN — 75% on time
More flights from Denver
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: DEN → BUF, nonstop flights by US airlines that report to the DOT. How we calculate this.