Route on-time record
BUF to DEN: most on-time flights and the best time to fly
Buffalo (Buffalo Niagara International Airport) to Denver (Denver International Airport). 614 nonstop flights in Jun 2025 to May 2026, 80% arrived within 15 minutes and 0.3% were cancelled. The most reliable flight number was United 1727 at 8:30 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
BUF → DEN
Buffalo to Denver: 614 nonstop flights a year
On time (12 months)
80%
Cancelled
0.3%
avg delay 13 min
Best time to leave
Before 9 AM
86% on time vs 54% 3 to 6 PM
Most reliable airline
United
84% chance on time
Lowest nonstop fare seen in the next two months: $416 (United 1727 on 2026-10-24). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · United 1727
8:30 AM → 10:13 AM3h 43m nonstop
Local times, typical schedule. Last flown 2026-05-31.
85%
chance on time
- On time (history)
- 85%
- Cancelled
- 0.3%
- Avg arrival delay
- 13 min
- Arrived on time 85% of the time (292 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 86% on time; 3 to 6 PM: 54%).
Strong track record · 292 flights
Find United 1727 fares Opens this date on Aviasales#2 · Southwest 435
3:25 PM → 5:00 PM3h 35m nonstop
Local times, typical schedule. Last flown 2026-05-30.
68%
chance on time
- On time (history)
- 38%
- Cancelled
- 0.0%
- Avg arrival delay
- 34 min
- Arrived on time 38% of the time (8 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (3 to 6 PM: 54% on time; Before 9 AM: 86%).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- 69% of its delay minutes came from the plane arriving late from an earlier flight.
Limited track record · 8 flights
Find Southwest 435 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines84%
293 flights · 85% on time as flown · 0.3% cancel
- Southwest Airlines78%
262 flights · 78% on time as flown · 0.4% cancel
- Frontier Airlines71%
59 flights · 64% on time as flown · 0.2% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM86%
408 flights · avg delay 10 min
- 9 AM to noon80%
66 flights · avg delay 17 min
- Noon to 3 PM86%
43 flights · avg delay 6 min
- 3 to 6 PM54%
92 flights · avg delay 27 min
Best day: Thursday (86%). Worst: Saturday (68%).
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Airline (crew, maintenance, boarding)34%
- Air traffic control and airport volume33%
- Late-arriving aircraft31%
- Severe weather3%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
BUF to DEN questions
- What time of day is best to fly BUF to DEN?
- Before 9 AM: 86% of flights arrived on time, against 54% for departures 3 to 6 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from BUF to DEN?
- United, with a season-adjusted 84% chance of operating and arriving on time over 293 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on BUF to DEN?
- May (70% on time); the best was October (87%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from BUF
- DEN to BUF (return)
- BUF to ORD 73%
- BUF to LGA 77%
- BUF to MCO 76%
- BUF to BWI 86%
- BUF to ATL 80%
- BUF to CLT 78%
- BUF to JFK 79%
- BUF to DCA 65%
- BUF to BOS 74%
- BUF to DTW 81%
- BUF to MDW 78%
- BUF to TPA 77%
Live status: FAA delays and ground stops