DEN → IAH Flight Reliability

Right now

Origin · DENNo disruption reported

Aviation weather is not currently a factor.

Updated 08:53 UTC

Denver airport profile →

Destination · IAHNo disruption reported

Aviation weather is not currently a factor.

Updated 08:53 UTC

Houston airport profile →

Route reliability

July 2023 – July 2026

Route Reliability Score

64/ 100Good

Better than 46% of comparable major US routes (4,598 compared)

Calculated from 14,972 flights. How this is calculated

On-time arrivals

76.8%

11,376 of 14,820

Cancellation rate

0.83%

124 cancelled

Median arrival delay

-4 min

Average 8.0 min

Severe delays

8.2%

60+ minutes late

Delay when late

64 min

Average, when 15+ min late

Flights analyzed

14,972

3 carriers

DEN → IAH arrives on time 76.8% of the time; the return trip, IAH → DEN, arrives on time 79.4% of the time, a 2.6-point gap between the two directions of the same city pair.

DEN → IAH spends 30.4 minutes on the ground on an 862-mile trip: 19.4 minutes from pushback to wheels-up at DEN and 11.0 minutes from touchdown to gate at IAH.

Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026

Why DEN → IAH flights are cancelled

July 2023 – July 2026

DEN → IAH cancelled 124 of 14,972 scheduled flights — about 1 in every 121. The reason filed most often was extreme weather, 50.8% of the cancellations coded on this route — about 1 in every 238 scheduled flights.

Share of cancellations

Weather50.8%

Airline39.5%

Air traffic9.7%

Security0.0%

Of 124 cancelled departures carrying a reason code.

What each reason means

Extreme weather1 in 238

Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.

63 cancellations, 50.8% of the total.

The airline1 in 306

Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.

49 cancellations, 39.5% of the total.

The air traffic system1 in 1,248

Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.

12 cancellations, 9.7% of the total.

Security—

A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.

0 cancellations, 0.0% of the total.

Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.

124 coded cancellations were recorded on DEN → IAH; the section appears from 50.

When it goes wrong

July 2023 – July 2026

One arrival in ten is worse than

48 min late

against a median of 4 min early

Arrived an hour or more late8.2%

Typical delay when late64 min

Cancelled0.83%

Landed somewhere else0.19%

Percentiles over 14,972 operations; cancelled and diverted flights are counted separately.

Will your connection be tight enough?

Layovers at IAH after arriving from DEN.

Connection buffer and chance of missing by layover length, DEN → IAH arrivals
Connection time	Chance of missing	Reads as
30 min	40%	Likely to miss
45 min	22%	High risk
60 min	15%	Some risk
90 min	8.1%	Some risk
120 min	4.8%	Low risk

This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.83% of the time and diverts 0.19% of the time, which a late arrival never shows up in.

Chance of missing is the share of 14,820 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.

The worst tenth of arrivals on this route land at least 48 minutes late (90th-percentile gate arrival delay), over 14,972 operations.

Any other layover length: connection checker.

Best time to fly

DEN → IAH flights departing 5–9 AM arrived on time 88.2% of the time, against 70.8% for 6–9 PM departures, a gap of 17.4 percentage points.

By day and hour

On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (DEN).

Hour of departure matters more than day of the week: hourly averages sit a typical 7.4 points from the route-wide rate, weekday averages 1.8 points.

On-time arrival rate for DEN to IAH by weekday and scheduled departure hour, local time. Each button reads out one slot.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
5 AM–6 AM
6 AM–7 AM
7 AM–8 AM
8 AM–9 AM
9 AM–10 AM
10 AM–11 AM
11 AM–12 PM
12 PM–1 PM
1 PM–2 PM
2 PM–3 PM
3 PM–4 PM
4 PM–5 PM
5 PM–6 PM
6 PM–7 PM
7 PM–8 PM
8 PM–9 PM

On-time rate, % · stronger color, fewer on time

60–69
70–79
80–89
90–99

Fewer than 120 flights, not scored

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · On time is arrival within 15 minutes of schedule. Cells round to whole percentages; the table shows one decimal.

No slot is named best or worst: too few reach 500 flights. Departures after 9 PM (512 flights) are not drawn: no slot in those hours has enough flights to score.

View as tableHide table

On-time arrival rate (%) with flights beneath, by scheduled departure hour and weekday for DEN to IAH. A dash means fewer than 120 flights, which are not scored.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
5 AM–6 AM	89.5% on time184 flights	94.2% on time174 flights	96.7% on time181 flights	93.6% on time191 flights	88.1% on time178 flights	88.6% on time178 flights	89.4% on time201 flights
6 AM–7 AM	38 flights, too few to score	14 flights, too few to score	17 flights, too few to score	34 flights, too few to score	38 flights, too few to score	22 flights, too few to score	33 flights, too few to score
7 AM–8 AM	87.7% on time189 flights	89.8% on time178 flights	89.3% on time178 flights	85.5% on time194 flights	85.2% on time199 flights	86.8% on time190 flights	86.4% on time199 flights
8 AM–9 AM	65 flights, too few to score	79 flights, too few to score	63 flights, too few to score	55 flights, too few to score	51 flights, too few to score	26 flights, too few to score	32 flights, too few to score
9 AM–10 AM	103 flights, too few to score	94 flights, too few to score	93 flights, too few to score	97 flights, too few to score	101 flights, too few to score	96 flights, too few to score	117 flights, too few to score
10 AM–11 AM	80 flights, too few to score	87 flights, too few to score	79 flights, too few to score	82 flights, too few to score	84 flights, too few to score	119 flights, too few to score	74 flights, too few to score
11 AM–12 PM	81.5% on time176 flights	82.6% on time169 flights	78.1% on time184 flights	78.3% on time176 flights	79.2% on time180 flights	78.0% on time165 flights	82.5% on time183 flights
12 PM–1 PM	91 flights, too few to score	95 flights, too few to score	96 flights, too few to score	90 flights, too few to score	86 flights, too few to score	65 flights, too few to score	57 flights, too few to score
1 PM–2 PM	68.9% on time166 flights	67.2% on time176 flights	72.2% on time180 flights	70.3% on time173 flights	75.3% on time167 flights	73.3% on time177 flights	76.4% on time177 flights
2 PM–3 PM	31 flights, too few to score	24 flights, too few to score	19 flights, too few to score	27 flights, too few to score	23 flights, too few to score	19 flights, too few to score	18 flights, too few to score
3 PM–4 PM	72.5% on time202 flights	76.9% on time200 flights	73.8% on time206 flights	71.2% on time199 flights	73.9% on time199 flights	75.3% on time182 flights	71.9% on time195 flights
4 PM–5 PM	114 flights, too few to score	114 flights, too few to score	113 flights, too few to score	106 flights, too few to score	111 flights, too few to score	77.2% on time123 flights	111 flights, too few to score
5 PM–6 PM	71.4% on time205 flights	73.8% on time206 flights	72.0% on time200 flights	64.4% on time206 flights	64.9% on time211 flights	70.5% on time193 flights	68.9% on time206 flights
6 PM–7 PM	87 flights, too few to score	71 flights, too few to score	69 flights, too few to score	84 flights, too few to score	89 flights, too few to score	95 flights, too few to score	82 flights, too few to score
7 PM–8 PM	72.2% on time179 flights	72.2% on time170 flights	77.4% on time168 flights	65.2% on time182 flights	67.7% on time190 flights	73.9% on time177 flights	68.5% on time180 flights
8 PM–9 PM	74.3% on time184 flights	69.8% on time194 flights	82.3% on time194 flights	70.9% on time182 flights	69.7% on time190 flights	77.9% on time197 flights	67.9% on time217 flights

By departure window

5–9 AM88.2%

9 AM–12 PM81.2%

12–3 PM73.4%

3–6 PM70.9%

6–9 PM70.8%

9 PM–5 AM74.5%

By departure hour

12 AM

3 AM

6 AM

9 AM

12 PM

3 PM

6 PM

9 PM

Why DEN → IAH runs late

July 2023 – July 2026

Late-arriving aircraft41.6%

the inbound aircraft was late, so this flight started late

Air traffic control28.2%

airspace and airport capacity, including weather-driven flow control

The airline26.9%

crew, maintenance, boarding and fueling, all within the carrier’s control

Weather3.2%

weather severe enough to stop this flight specifically

Security<0.1%

screening or terminal security incidents

Share of the delay minutes US DOT attributed to each cause for DEN → IAH. Only delays of 15 minutes or more are attributed.

Late-arriving aircraft is the largest cause on DEN → IAH, at 41.6%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 88.2% of the time and 6–9 PM departures 70.8%.

How this route holds up in bad weather

July 2023 – July 2026

Bad weather raises cancellations by a similar amount at both ends of DEN to IAH: 4.0 times the normal rate at DEN and 3.4 times at IAH. Cancelled in bad weather against normal hours: DEN 2.8% against 0.7%, IAH 4.1% against 1.2%. Flights that did leave DEN in bad weather arrived on time 51.5% of the time, against 78.8% in normal hours.

Bad weather and normal hours at the airports

Scheduled departures, July 2023 – July 2026

Departures from DEN and IAH in hours of bad weather and in normal hours
Departures from	DEN	IAH
Cancelled in bad weather	2.8%	4.1%
Cancelled in normal hours	0.7%	1.2%
Arrived on time, bad weather	51.5%	63.8%
Arrived on time, normal hours	78.8%	78.6%
Departures in bad weather	92,610	28,922

United Airlines (1.5% cancelled against 3.5% for the other carriers at DEN) and Southwest Airlines (2.4% cancelled against 3.1% for the other carriers at DEN) cancelled fewer departures from DEN in bad weather than the other carriers there did in the same months. None of the route’s other carriers was clearly worse.

This route’s airlines in bad weather at DEN

All departures from DEN

Cancellation rates in bad weather at DEN for the airlines that fly DEN to IAH, against the other carriers at DEN in the same months
Airline	Bad-weather departures	Cancelled	Other carriers
United Airlines	30,853	1.5%below the others	3.5%
Southwest Airlines	28,467	2.4%below the others	3.1%
Frontier Airlines	6,740	3.1%about level	2.8%

These are airport figures, not route figures: every scheduled departure from DEN and IAH, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from DEN on every route.

Weather source and limits. In full: DEN (airlines), IAH, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.

Airlines on this route

Carriers with at least 200 flights, by the airline that operated each one.

Airlines on this route
Carrier	Flights	On time	Cancelled	Median delay	Severe
United Airlines	11,809	77.2%	0.77%	-4 min	8.2%
Frontier Airlines	2,081	74.9%	1.06%	-7 min	9.1%
Southwest Airlines	1,082	76.0%	1.02%	-3 min	6.9%

United Airlines flew 78.9% of the 14,972 flights listed.

United Airlines arrived on time 2.3 percentage points more often than Frontier Airlines on this route.

Flights on this route

Flight numbers with at least 600 operations here and still on the schedule.

Flights on this route
Flight	Scheduled	Operations	On time
UA489 United Airlines	3:40 PM	965	71.1%
UA475 United Airlines	7:20 PM	940	72.0%
UA1720 United Airlines	7:45 AM	742	89.4%
UA1829 United Airlines	1:25 PM	651	71.1%
F93206 Frontier Airlines	7:00 AM	621	80.4%
UA320 United Airlines	5:00 AM	605	94.7%

UA320 (5:00 AM) arrived on time 94.7% of the time, 23.6 points more often than UA1829 (1:25 PM) at 71.1%.

Weekly and seasonal patterns

By day of week

Mon76.2%

Tue78.7%

Wed79.6%

Thu74.7%

Fri74.5%

Sat77.6%

Sun76.3%

Wednesday is historically the most reliable day and Friday the least, a gap of 5.1 percentage points.

By month

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

July is historically the weakest month and October the strongest, a spread of 19.7 percentage points.

Reliability over time

July 2023 – July 2026

24

25

26

Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 79.5% against 76.9% in the 12 months before — improving by 2.6 percentage points.

Data and methodology

Calculated by FlyerIntel from 14,972 DEN → IAH flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.

Full methodology · Data sources · Report a problem

Analysis last recomputed September 26, 2026

DEN airport IAH airport Return direction IAH → DEN

DEN→IAH

Right now

Route reliability

Why DEN → IAH flights are cancelled

Share of cancellations

What each reason means

When it goes wrong

Will your connection be tight enough?

Best time to fly

By day and hour

By departure window

By departure hour

Why DEN → IAH runs late

How this route holds up in bad weather

Bad weather and normal hours at the airports

This route’s airlines in bad weather at DEN

Airlines on this route

Flights on this route

Weekly and seasonal patterns

By day of week

By month

Reliability over time

Data and methodology