Airport month record

DENMAY

Denver International in May 2026

Departures: 27,406
Month: May 2026
National, same month: 78.6%
Carriers: 10

Historical statistics for May 2026, not live status or a forecast for this year’s May. For today’s conditions at DEN, see live FAA status.

DEN in May lands a B+, 2 points worse than the national rate of 78.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 27,406 flights, of which Delta Air Lines flew 1,051 at 86.0% on time.

Delta Air Lines is the most reliable of the six carriers covered here at 86.0% on time across 1,051 flights.

On time

76.4%

Arrivals under 15 minutes late, of 27,256 completed departures

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.28%

Nationally in May: 0.92%

Whole year

76.3%

DEN across all twelve months

These figures cover 27,406 departures from Denver International in May 2026. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

May next to DEN's other months

Against DEN's own year, May ran level with the twelve-month rate of 76.3%, which makes it number eight of twelve months, best first. Cancellations were unusually low for DEN in May, at 0.28% against 0.79% across the year. Either side of it, April ran 82.5% on time and June 67.1%, so this month sits in line with its neighbours.

DEN month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	29,433	63.0%	77 min	1.48%	D
August 2025	28,084	70.1%	69 min	0.73%	C+
September 2025	26,548	79.4%	54 min	0.12%	B+
October 2025	27,763	80.8%	52 min	0.13%	B+
November 2025	25,280	84.7%	62 min	1.44%	B
December 2025	26,026	74.3%	68 min	0.64%	C+
January 2026	24,484	82.3%	60 min	1.69%	B
February 2026	23,046	82.4%	69 min	0.88%	B+
March 2026	27,089	76.8%	72 min	1.50%	B
April 2026	25,345	82.5%	56 min	0.27%	B+
May 2026 (this page)	27,406	76.4%	58 min	0.28%	B+
June 2026	28,634	67.1%	64 min	0.41%	C+

Departure window

The best time of day to leave DEN in May

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am2,282 flights92.8%
8am–11am5,691 flights85.7%
11am–2pm5,786 flights80.7%
2pm–5pm4,085 flights75.8%
5pm–8pm6,058 flights64.1%
8pm–5am3,504 flights65.7%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 64.1% on time, against 92.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 6,058 flights scheduled in it.

Across the week, Saturday is the strongest day at 81.8% on time and Monday the weakest at 72.2%. 10 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at DEN in May

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.0% of the time; Southwest Airlines manages 65.5%. Sample sizes sit next to every figure, because a two-point gap across 7,397 flights means less than a ten-point one.

Carriers at DEN in May 2026
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	9,440	79.1%	54 min	0.10%	B+
Southwest Airlines	7,397	65.5%	51 min	0.24%	C+
SkyWest Airlines	6,331	82.1%	69 min	0.43%	B+
Frontier Airlines	1,970	79.9%	60 min	0.20%	B+
Delta Air Lines	1,051	86.0%	62 min	0.86%	A+
American Airlines	799	77.7%	98 min	1.25%	B
Alaska Airlinesthin sample	253	86.2%	46 min	0.00%	A+
JetBlue Airwaysthin sample	98	78.4%	46 min	1.02%	B
Envoy Airthin sample	36	72.2%	170 min	0.00%	C+
Allegiant Airthin sample	31	71.0%	77 min	0.00%	C+

The spread between Delta and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.

Route by route

Busiest routes out of DEN in May

Routes from DEN in May 2026
Route	Flights	On time	Avg delay	Cancelled	Grade
DEN to PHX · Phoenix	768	75.7%	64 min	0.52%	B+
DEN to LAX · Los Angeles	687	79.6%	56 min	0.15%	B+
DEN to SLC · Salt Lake City	665	81.2%	55 min	0.00%	B+
DEN to LAS · Las Vegas	640	77.2%	63 min	0.62%	B+
DEN to ORD · Chicago	583	76.0%	51 min	0.00%	B+
DEN to SEA · Seattle	546	76.6%	50 min	0.00%	B+
DEN to MSP · Minneapolis	533	77.6%	59 min	0.19%	B+
DEN to DFW · Dallas-Fort Worth	533	74.3%	86 min	1.69%	C
DEN to SAN · San Diego	515	77.2%	49 min	0.19%	B+
DEN to SFO · San Francisco	483	53.5%	57 min	0.00%	F+
DEN to ATL · Atlanta	482	74.8%	56 min	0.83%	C+
DEN to AUS · Austin	467	74.2%	57 min	0.64%	C+
DEN to COS · Colorado Springs	428	76.8%	60 min	0.23%	B+
DEN to IAH · Houston	412	81.8%	57 min	0.00%	B+
DEN to LGA · New York	397	76.3%	60 min	1.01%	B
DEN to MCI · Kansas City	382	71.8%	61 min	0.26%	C+
DEN to PDX · Portland	366	79.0%	45 min	0.00%	B+
DEN to MCO · Orlandothin sample	351	78.4%	50 min	0.00%	B+
DEN to BOS · Bostonthin sample	323	75.8%	56 min	0.31%	B+
DEN to SMF · Sacramentothin sample	322	71.4%	49 min	0.00%	C+
DEN to SNA · Santa Anathin sample	319	82.4%	35 min	0.00%	B+
DEN to IAD · Washingtonthin sample	316	80.4%	58 min	0.00%	B+
DEN to BNA · Nashvillethin sample	314	69.7%	47 min	0.00%	C+
DEN to STL · St. Louisthin sample	312	73.0%	52 min	0.00%	C+
DEN to ABQ · Albuquerquethin sample	296	77.1%	49 min	0.34%	B+

Delay causes

What held DEN up in May

One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 369,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
44%
Carrier
33%
National Airspace System
20%
Extreme weather
3%
Security
0%

44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 369,000 reported delay minutes here, that single category outweighs weather by 13 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 369,157 reported delay minutes.

Cancellations are rare at 0.28%, below the national 0.92% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

6.8% of arrivals land an hour or more late, close to the national 7.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

What to do with this

Flying from DEN in May

For a May trip through DEN: expect 76.4% on time and 0.28% cancelled, going by May 2026. The 5am–8am window was the strongest part of the day.

Denver International (DEN), the whole year
DEN in July63.0%
DEN in August70.1%
DEN in September79.4%
DEN in October80.8%
DEN in November84.7%
DEN in December74.3%
DEN in January82.3%
DEN in February82.4%
DEN in March76.8%
DEN in April82.5%
DEN in June67.1%

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures