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2,182 km · Domestic

Buffalo Niagara (BUF) – Denver (DEN)

In July 2026, 138 flights operated between Buffalo Niagara and Denver (both directions), and 55.8% left on time, according to the US BTS.

Official · July 2026 according to the US BTS only airlines required to report on-time data to the US DOT

Flights per month

Only complete months are shown. A month appears once the source has published every day of it.

The most recent periods19 periods
PeriodFlights operated 2025Flights operated 2026Change vs last year
January2428▲ 16.7%
February3872▲ 89.5%
March5766▲ 15.8%
April6066▲ 10.0%
May8872▼ 18.2%
June157130▼ 17.2%
July165138▼ 16.4%
August162––
September154––
October140–in progress
November104––
December39––
Year to date (Jan–Jul)589572▼ 2.9%

On-time departures by month

Departures within 15 minutes of schedule.

The most recent periods19 periods
PeriodOn-time departures 2025On-time departures 2026Change vs last year
January62.5%85.7%▲ 37.1%
February63.2%72.2%▲ 14.2%
March75.4%84.8%▲ 12.5%
April70.0%86.4%▲ 23.4%
May55.7%80.6%▲ 44.7%
June70.7%60.0%▼ 15.1%
July65.5%55.8%▼ 14.8%
August67.3%––
September70.1%––
October85.7%–in progress
November83.7%––
December69.2%––
Year-to-date average (Jan–Jul)66.1%75.1%▲ 13.5%

Cancelled flights by month

The most recent periods19 periods
PeriodCancelled flights 2025Cancelled flights 2026Change vs last year
January00–
February01–
March10▼ 100.0%
April00–
May00–
June10▼ 100.0%
July10▼ 100.0%
August0––
September0––
October0–in progress
November0––
December1––
Year to date (Jan–Jul)31▼ 66.7%

Airlines on this route

  1. Southwest Airlines 54.0%
  2. United Airlines 38.2%
  3. Frontier Airlines 7.8%

Oct 1, 2024 – Jul 31, 2026

By direction

BUF → DEN

Scheduled flights
953
Flights operated
951
Cancelled
2 · 0.2%
On-time departures
79.3%

DEN → BUF

Scheduled flights
954
Flights operated
951
Cancelled
3 · 0.3%
On-time departures
63.7%

BUF → DEN and DEN → BUF counted separately.

Airlines on this route

Oct 1, 2024 – Jul 31, 2026
AirlineScheduled flights Share On-time departures Cancelled
Southwest Airlines WN 1,030 54.0% 66.6% 4
United Airlines UA 729 38.2% 78.0% 1
Frontier Airlines F9 148 7.8% 73.6% 0

Shares are of scheduled flights in the period shown. Codeshare flights are counted once, under the operating airline.

Flight timing & delays

Historical departures, grouped by the scheduled local time at the departure airport. These are recorded outcomes, not a forecast for your flight.

Times are local to the departure airport of each flight; both directions are combined.

US domestic sectors recorded by BTS

Source: the US BTS · Oct 12, 2024 → Jul 31, 2026

Lowest average delay08:00–09:006.8min · 349 recorded · 348 measured
Gap to highest-delay hour21.8min08:00 ↔ 17:00
Recorded flights1,907BUF–DEN

Departure hour

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · Fewer than 200 measured departures · 63 recorded · 63 measured · Source: the US BTS 06:00 · Fewer than 200 measured departures · 31 recorded · 31 measured · Source: the US BTS 07:00 · Fewer than 200 measured departures · 99 recorded · 99 measured · Source: the US BTS 08:00 · 87.4% · 349 recorded · 348 measured · Source: the US BTS 09:00 · Fewer than 200 measured departures · 112 recorded · 112 measured · Source: the US BTS 10:00 · Fewer than 200 measured departures · 117 recorded · 116 measured · Source: the US BTS 11:00 · Fewer than 200 measured departures · 71 recorded · 71 measured · Source: the US BTS 12:00 · Fewer than 200 measured departures · 86 recorded · 86 measured · Source: the US BTS 13:00 · Fewer than 200 measured departures · 37 recorded · 37 measured · Source: the US BTS 14:00 · Fewer than 200 measured departures · 78 recorded · 78 measured · Source: the US BTS 15:00 · Fewer than 200 measured departures · 34 recorded · 34 measured · Source: the US BTS 16:00 · Fewer than 200 measured departures · 127 recorded · 126 measured · Source: the US BTS 17:00 · 63.8% · 519 recorded · 519 measured · Source: the US BTS 18:00 · Fewer than 200 measured departures · 30 recorded · 28 measured · Source: the US BTS 19:00 · Fewer than 200 measured departures · 136 recorded · 136 measured · Source: the US BTS 20:00 · Fewer than 200 measured departures · 18 recorded · 18 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · Fewer than 200 measured departures · 63 recorded · 63 measured · Source: the US BTS 06:00 · Fewer than 200 measured departures · 31 recorded · 31 measured · Source: the US BTS 07:00 · Fewer than 200 measured departures · 99 recorded · 99 measured · Source: the US BTS 08:00 · 6.8 min · 349 recorded · 348 measured · Source: the US BTS 09:00 · Fewer than 200 measured departures · 112 recorded · 112 measured · Source: the US BTS 10:00 · Fewer than 200 measured departures · 117 recorded · 116 measured · Source: the US BTS 11:00 · Fewer than 200 measured departures · 71 recorded · 71 measured · Source: the US BTS 12:00 · Fewer than 200 measured departures · 86 recorded · 86 measured · Source: the US BTS 13:00 · Fewer than 200 measured departures · 37 recorded · 37 measured · Source: the US BTS 14:00 · Fewer than 200 measured departures · 78 recorded · 78 measured · Source: the US BTS 15:00 · Fewer than 200 measured departures · 34 recorded · 34 measured · Source: the US BTS 16:00 · Fewer than 200 measured departures · 127 recorded · 126 measured · Source: the US BTS 17:00 · 28.6 min · 519 recorded · 519 measured · Source: the US BTS 18:00 · Fewer than 200 measured departures · 30 recorded · 28 measured · Source: the US BTS 19:00 · Fewer than 200 measured departures · 136 recorded · 136 measured · Source: the US BTS 20:00 · Fewer than 200 measured departures · 18 recorded · 18 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · 63 · 63 recorded · 63 measured · Source: the US BTS 06:00 · 31 · 31 recorded · 31 measured · Source: the US BTS 07:00 · 99 · 99 recorded · 99 measured · Source: the US BTS 08:00 · 349 · 349 recorded · 348 measured · Source: the US BTS 09:00 · 112 · 112 recorded · 112 measured · Source: the US BTS 10:00 · 117 · 117 recorded · 116 measured · Source: the US BTS 11:00 · 71 · 71 recorded · 71 measured · Source: the US BTS 12:00 · 86 · 86 recorded · 86 measured · Source: the US BTS 13:00 · 37 · 37 recorded · 37 measured · Source: the US BTS 14:00 · 78 · 78 recorded · 78 measured · Source: the US BTS 15:00 · 34 · 34 recorded · 34 measured · Source: the US BTS 16:00 · 127 · 127 recorded · 126 measured · Source: the US BTS 17:00 · 519 · 519 recorded · 519 measured · Source: the US BTS 18:00 · 30 · 30 recorded · 28 measured · Source: the US BTS 19:00 · 136 · 136 recorded · 136 measured · Source: the US BTS 20:00 · 18 · 18 recorded · 18 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

View the figures
Departure hourOn-time departuresAverage departure delayWith departure timeRecorded flights
00:00No observations———
01:00No observations———
02:00No observations———
03:00No observations———
04:00No observations———
05:00Fewer than 200 measured departures—6363
06:00Fewer than 200 measured departures—3131
07:00Fewer than 200 measured departures—9999
08:0087.4%6.8 min348349
09:00Fewer than 200 measured departures—112112
10:00Fewer than 200 measured departures—116117
11:00Fewer than 200 measured departures—7171
12:00Fewer than 200 measured departures—8686
13:00Fewer than 200 measured departures—3737
14:00Fewer than 200 measured departures—7878
15:00Fewer than 200 measured departures—3434
16:00Fewer than 200 measured departures—126127
17:0063.8%28.6 min519519
18:00Fewer than 200 measured departures—2830
19:00Fewer than 200 measured departures—136136
20:00Fewer than 200 measured departures—1818
21:00No observations———
22:00No observations———
23:00No observations———

Day of week

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
Monday · 70.1% · 296 recorded · 294 measured · Source: the US BTS Tuesday · 72.9% · 204 recorded · 203 measured · Source: the US BTS Wednesday · 73.3% · 217 recorded · 217 measured · Source: the US BTS Thursday · 70.4% · 240 recorded · 240 measured · Source: the US BTS Friday · 73.4% · 304 recorded · 304 measured · Source: the US BTS Saturday · 70.2% · 340 recorded · 339 measured · Source: the US BTS Sunday · 71.2% · 306 recorded · 305 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
Monday · 19.7 min · 296 recorded · 294 measured · Source: the US BTS Tuesday · 21.3 min · 204 recorded · 203 measured · Source: the US BTS Wednesday · 19.6 min · 217 recorded · 217 measured · Source: the US BTS Thursday · 15.4 min · 240 recorded · 240 measured · Source: the US BTS Friday · 13.7 min · 304 recorded · 304 measured · Source: the US BTS Saturday · 17.8 min · 340 recorded · 339 measured · Source: the US BTS Sunday · 18.0 min · 306 recorded · 305 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
Monday · 296 · 296 recorded · 294 measured · Source: the US BTS Tuesday · 204 · 204 recorded · 203 measured · Source: the US BTS Wednesday · 217 · 217 recorded · 217 measured · Source: the US BTS Thursday · 240 · 240 recorded · 240 measured · Source: the US BTS Friday · 304 · 304 recorded · 304 measured · Source: the US BTS Saturday · 340 · 340 recorded · 339 measured · Source: the US BTS Sunday · 306 · 306 recorded · 305 measured · Source: the US BTS

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View the figures
Day of weekOn-time departuresAverage departure delayWith departure timeRecorded flights
Monday70.1%19.7 min294296
Tuesday72.9%21.3 min203204
Wednesday73.3%19.6 min217217
Thursday70.4%15.4 min240240
Friday73.4%13.7 min304304
Saturday70.2%17.8 min339340
Sunday71.2%18.0 min305306

Month of year

Months combine the same calendar month across the years shown; this is a seasonal pattern, not a monthly time series.

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
Jan · Fewer than 200 measured departures · 52 recorded · 52 measured · Source: the US BTS Feb · Fewer than 200 measured departures · 111 recorded · 110 measured · Source: the US BTS Mar · Fewer than 200 measured departures · 124 recorded · 123 measured · Source: the US BTS Apr · Fewer than 200 measured departures · 126 recorded · 126 measured · Source: the US BTS May · Fewer than 200 measured departures · 160 recorded · 160 measured · Source: the US BTS Jun · 65.9% · 288 recorded · 287 measured · Source: the US BTS Jul · 61.1% · 304 recorded · 303 measured · Source: the US BTS Aug · Fewer than 200 measured departures · 162 recorded · 162 measured · Source: the US BTS Sep · Fewer than 200 measured departures · 154 recorded · 154 measured · Source: the US BTS Oct · Fewer than 200 measured departures · 190 recorded · 190 measured · Source: the US BTS Nov · Fewer than 200 measured departures · 160 recorded · 160 measured · Source: the US BTS Dec · Fewer than 200 measured departures · 76 recorded · 75 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
Jan · Fewer than 200 measured departures · 52 recorded · 52 measured · Source: the US BTS Feb · Fewer than 200 measured departures · 111 recorded · 110 measured · Source: the US BTS Mar · Fewer than 200 measured departures · 124 recorded · 123 measured · Source: the US BTS Apr · Fewer than 200 measured departures · 126 recorded · 126 measured · Source: the US BTS May · Fewer than 200 measured departures · 160 recorded · 160 measured · Source: the US BTS Jun · 21.9 min · 288 recorded · 287 measured · Source: the US BTS Jul · 24.8 min · 304 recorded · 303 measured · Source: the US BTS Aug · Fewer than 200 measured departures · 162 recorded · 162 measured · Source: the US BTS Sep · Fewer than 200 measured departures · 154 recorded · 154 measured · Source: the US BTS Oct · Fewer than 200 measured departures · 190 recorded · 190 measured · Source: the US BTS Nov · Fewer than 200 measured departures · 160 recorded · 160 measured · Source: the US BTS Dec · Fewer than 200 measured departures · 76 recorded · 75 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
Jan · 52 · 52 recorded · 52 measured · Source: the US BTS Feb · 111 · 111 recorded · 110 measured · Source: the US BTS Mar · 124 · 124 recorded · 123 measured · Source: the US BTS Apr · 126 · 126 recorded · 126 measured · Source: the US BTS May · 160 · 160 recorded · 160 measured · Source: the US BTS Jun · 288 · 288 recorded · 287 measured · Source: the US BTS Jul · 304 · 304 recorded · 303 measured · Source: the US BTS Aug · 162 · 162 recorded · 162 measured · Source: the US BTS Sep · 154 · 154 recorded · 154 measured · Source: the US BTS Oct · 190 · 190 recorded · 190 measured · Source: the US BTS Nov · 160 · 160 recorded · 160 measured · Source: the US BTS Dec · 76 · 76 recorded · 75 measured · Source: the US BTS

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View the figures
Month of yearOn-time departuresAverage departure delayWith departure timeRecorded flights
JanFewer than 200 measured departures—5252
FebFewer than 200 measured departures—110111
MarFewer than 200 measured departures—123124
AprFewer than 200 measured departures—126126
MayFewer than 200 measured departures—160160
Jun65.9%21.9 min287288
Jul61.1%24.8 min303304
AugFewer than 200 measured departures—162162
SepFewer than 200 measured departures—154154
OctFewer than 200 measured departures—190190
NovFewer than 200 measured departures—160160
DecFewer than 200 measured departures—7576

Delay and on-time rates need at least 200 measured departures per bucket. Smaller samples remain visible in the flight-count chart. An empty slot means no observations, not zero flights.

Recorded outcomes

  • On time 71.3% 1,360
  • Delayed >15 min 28.4% 542
  • Cancelled 0.3% 5
  • Missing departure time 0.0% 0

All recorded flights with a known scheduled local time, counted once. Missing actual times are shown separately.

On time means departing no more than 15 minutes after schedule. Cancelled flights and flights missing departure times are excluded from the on-time rate and average delay.

Flight numbers on this route

16
16 of 16
Flight numbersBy direction DeparturesOn time
UA1727 BUF → DEN 364 87.3%
UA2473 DEN → BUF 160 71.3%
F992751 BUF → DEN 74 68.9%
F992752 DEN → BUF 74 78.4%
UA248 DEN → BUF 71 67.6%
WN3120 BUF → DEN 61 95.1%
WN3156 DEN → BUF 60 30.5%
WN3907 DEN → BUF 50 58.0%
WN889 BUF → DEN 50 68.0%
WN954 BUF → DEN 50 68.0%
WN1396 DEN → BUF 39 41.0%
UA1593 DEN → BUF 36 38.9%
WN1927 DEN → BUF 33 51.5%
UA762 DEN → BUF 32 90.6%
WN2140 BUF → DEN 30 93.1%
WN2270 DEN → BUF 30 75.9%

Flight numbers are the codes sold on tickets. On shared flights one aircraft can carry several of them. Only numbers with at least 30 flights have a page.

Monthly figures
PeriodFlights operated Change vs last yearCancelled On-time departures
July 2026 138 −16.4% 0 55.8%
June 2026 130 −17.2% 0 60.0%
May 2026 72 −18.2% 0 80.6%
April 2026 66 +10.0% 0 86.4%
March 2026 66 +15.8% 0 84.8%
February 2026 72 +89.5% 1 72.2%
January 2026 28 +16.7% 0 85.7%
December 2025 39 +8.3% 1 69.2%
November 2025 104 +85.7% 0 83.7%
October 2025 140 +180.0% 0 85.7%
September 2025 154 0 70.1%
August 2025 162 0 67.3%
July 2025 165 1 65.5%
June 2025 157 1 70.7%
May 2025 88 0 55.7%
April 2025 60 0 70.0%
March 2025 57 1 75.4%
February 2025 38 0 63.2%
January 2025 24 0 62.5%
December 2024 36 0 72.2%
November 2024 56 0 82.1%
October 2024 50 0 86.0%

How to read this chart

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