Denver International in September 2025

80.3%departed on time

BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.

In September 2025, reporting carriers scheduled 26,548 domestic departures from Denver International (DEN). 80.3% left less than 15 minutes late and 79.2% reached their destination on time; 0.1% were cancelled.

Nationally that month, 83.1% of flights departed on time and 82.8% arrived on time, so DEN departures were 2.8 points below the national departure figure.

A year earlier, in September 2024, the airport had 26,146 departures with 83.3% leaving on time: a change of −3.0 points, with flights up 2%.

Flights arriving at DEN that month were on time 80.8% of the time (26,546 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 43%, air carrier 32% and national aviation system 23%.

On time 79.2%
Arrived 15+ minutes late 20.5%
Cancelled 0.1%
Diverted 0.2%

Every scheduled departure from DEN in September 2025, judged by arrival at the destination.

September 2025 against a year earlier, the airport's year and the nation

Measure	Sep 2025	Sep 2024	DEN, 12 months to Jul 2026	All reported flights, Sep 2025
Departed on time	80.3%	83.3%	75.7%	83.1%
Arrived on time	79.2%	84.4%	76.1%	82.8%
Cancelled	0.1%	0.2%	0.7%	0.5%
Average departure delay (late minutes only)	12.3 min	10.5 min	16.5 min	12.2 min
Scheduled departures a day	885	872	875	18,748
Scheduled departures	26,548	26,146	319,208	562,439

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
UA United Airlines	8,932	34%	80.3%	5.1 min	0.1%
WN Southwest Airlines	7,301	28%	72.4%	10.5 min	0.1%
OO SkyWest Airlines	6,403	24%	84.3%	1.4 min	0.0%
F9 Frontier Airlines	1,864	7%	77.7%	6.0 min	0.1%
DL Delta Air Lines	991	4%	87.3%	-2.7 min	0.0%
AA American Airlines	725	3%	80.3%	5.1 min	1.1%
AS Alaska Airlines	200	1%	79.5%	2.4 min	0.0%
B6 JetBlue Airways	82	0%	72.0%	20.7 min	1.2%
G4 Allegiant Air	42	0%	85.7%	1.8 min	0.0%
MQ Envoy Air	8	0%	87.5%	-9.7 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
DEN–PHX	Denver to Phoenix	665	75.9%	11.3 min	1.1%
DEN–LAX	Denver to Los Angeles	650	83.1%	0.8 min	0.2%
DEN–SLC	Denver to Salt Lake City	644	82.1%	3.1 min	0.0%
DEN–ORD	Denver to Chicago	604	77.6%	6.3 min	0.0%
DEN–SEA	Denver to Seattle	575	78.6%	2.5 min	0.0%
DEN–LAS	Denver to Las Vegas	537	70.9%	12.3 min	0.2%
DEN–MSP	Denver to Minneapolis	527	77.4%	6.6 min	0.0%
DEN–DFW	Denver to Dallas/Fort Worth	463	78.2%	5.2 min	1.5%
DEN–SFO	Denver to San Francisco	451	74.3%	7.4 min	0.0%
DEN–ATL	Denver to Atlanta	450	84.9%	0.8 min	0.0%
DEN–COS	Denver to Colorado Springs	443	79.0%	5.6 min	0.0%
DEN–SAN	Denver to San Diego	411	72.0%	13.8 min	0.7%

By scheduled departure hour

On-time share:under 62%6270768288% and over

Share of departures that left less than 15 minutes late, by scheduled hour (local time), September 2025.

Delay causes

BTS cause category	Share of delay minutes	National, Sep 2025	Minutes
Air carrier	31.6%	34.3%	92,255
Late-arriving aircraft	42.5%	37.4%	124,096
National Aviation System	23.1%	22.6%	67,389
Extreme weather	2.7%	5.6%	7,896
Security	0.0%	0.1%	84

291,720 delay minutes on 5,454 flights that arrived 15 or more minutes late and carried a cause report. Carriers assign the categories; see what each category means.

Questions and answers

How many flights left DEN on time in September 2025?

80.3% of 26,548 scheduled domestic departures left less than 15 minutes late, and 79.2% reached their destination on time. The national figures that month were 83.1% and 82.8%.

How does that compare with a year earlier?

In September 2024, 83.3% of 26,146 departures left on time and 0.2% were cancelled, against 80.3% and 0.1% in September 2025.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for September 2025; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for DEN · methodology · corrections.