ATL → IAH Flight Reliability

Right now

Origin · ATLNo disruption reported

Aviation weather is not currently a factor.

Updated 07:52 UTC

Atlanta airport profile →

Destination · IAHNo disruption reported

Aviation weather is not currently a factor.

Updated 07:53 UTC

Houston airport profile →

Route reliability

July 2023 – July 2026

Route Reliability Score

57/ 100Fair

Better than 28% of comparable major US routes (4,598 compared)

Calculated from 14,365 flights. How this is calculated

On-time arrivals

75.4%

10,621 of 14,087

Cancellation rate

1.66%

238 cancelled

Median arrival delay

-3 min

Average 10.6 min

Severe delays

8.9%

60+ minutes late

Delay when late

68 min

Average, when 15+ min late

Flights analyzed

14,365

4 carriers

ATL → IAH arrives on time 75.4% of the time; the return trip, IAH → ATL, arrives on time 76.7% of the time.

ATL → IAH spends 28.5 minutes on the ground on a 689-mile trip: 17.8 minutes from pushback to wheels-up at ATL and 10.7 minutes from touchdown to gate at IAH.

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

Why ATL → IAH flights are cancelled

July 2023 – July 2026

ATL → IAH cancelled 238 of 14,365 scheduled flights — about 1 in every 60. The reason filed most often was extreme weather, 48.7% of the cancellations coded on this route — about 1 in every 124 scheduled flights.

Share of cancellations

Weather48.7%

Airline47.5%

Air traffic3.8%

Security0.0%

Of 238 cancelled departures carrying a reason code.

What each reason means

Extreme weather1 in 124

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

116 cancellations, 48.7% of the total.

The airline1 in 127

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

113 cancellations, 47.5% of the total.

The air traffic system1 in 1,596

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

9 cancellations, 3.8% 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.

238 coded cancellations were recorded on ATL → IAH; the section appears from 50.

When it goes wrong

July 2023 – July 2026

One arrival in ten is worse than

53 min late

against a median of 3 min early

Arrived an hour or more late8.9%

Typical delay when late68 min

Cancelled1.66%

Landed somewhere else0.28%

Percentiles over 14,365 operations; cancelled and diverted flights are counted separately.

Will your connection be tight enough?

Layovers at IAH after arriving from ATL.

Connection buffer and chance of missing by layover length, ATL → IAH arrivals
Connection time	Chance of missing	Reads as
30 min	42%	Likely to miss
45 min	24%	High risk
60 min	16%	High risk
90 min	8.7%	Some risk
120 min	5.4%	Some 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 1.66% of the time and diverts 0.28% of the time, which a late arrival never shows up in.

Chance of missing is the share of 14,087 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 53 minutes late (90th-percentile gate arrival delay), over 14,365 operations.

Any other layover length: connection checker.

Best time to fly

ATL → IAH flights departing 5–9 AM arrived on time 83.8% of the time, against 66.8% for 6–9 PM departures, a gap of 17.0 percentage points.

By day and hour

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

Hour of departure matters more than day of the week: hourly averages sit a typical 7.8 points from the route-wide rate, weekday averages 2.1 points.

On-time arrival rate for ATL to IAH by weekday and scheduled departure hour, local time. Each button reads out one slot.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
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
9 PM–10 PM
10 PM–11 PM

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

55–59
60–64
65–69
70–74
75–79
80–84
85–89

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 before 7 AM and after 11 PM (428 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 ATL to IAH. A dash means fewer than 120 flights, which are not scored.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
7 AM–8 AM	85.2% on time297 flights	85.3% on time282 flights	81.8% on time290 flights	80.8% on time292 flights	83.6% on time303 flights	84.9% on time215 flights	87.8% on time304 flights
8 AM–9 AM	40 flights, too few to score	45 flights, too few to score	48 flights, too few to score	38 flights, too few to score	34 flights, too few to score	102 flights, too few to score	60 flights, too few to score
9 AM–10 AM	78.8% on time188 flights	83.0% on time165 flights	81.8% on time151 flights	79.2% on time205 flights	85.5% on time198 flights	77.6% on time160 flights	80.4% on time167 flights
10 AM–11 AM	107 flights, too few to score	109 flights, too few to score	90 flights, too few to score	91 flights, too few to score	98 flights, too few to score	66 flights, too few to score	91 flights, too few to score
11 AM–12 PM	82.7% on time127 flights	102 flights, too few to score	117 flights, too few to score	84.1% on time132 flights	85.3% on time137 flights	114 flights, too few to score	116 flights, too few to score
12 PM–1 PM	107 flights, too few to score	79.2% on time122 flights	75.0% on time120 flights	117 flights, too few to score	114 flights, too few to score	81 flights, too few to score	99 flights, too few to score
1 PM–2 PM	99 flights, too few to score	99 flights, too few to score	95 flights, too few to score	89 flights, too few to score	99 flights, too few to score	92 flights, too few to score	90 flights, too few to score
2 PM–3 PM	95 flights, too few to score	86 flights, too few to score	67 flights, too few to score	105 flights, too few to score	92 flights, too few to score	52 flights, too few to score	100 flights, too few to score
3 PM–4 PM	71.7% on time194 flights	73.9% on time162 flights	78.9% on time180 flights	78.8% on time184 flights	71.3% on time203 flights	77.9% on time203 flights	68.8% on time176 flights
4 PM–5 PM	115 flights, too few to score	101 flights, too few to score	101 flights, too few to score	67.5% on time122 flights	114 flights, too few to score	75 flights, too few to score	60.8% on time124 flights
5 PM–6 PM	66.5% on time169 flights	74.2% on time132 flights	75.7% on time136 flights	58.0% on time170 flights	57.2% on time168 flights	109 flights, too few to score	63.2% on time173 flights
6 PM–7 PM	53 flights, too few to score	99 flights, too few to score	104 flights, too few to score	70 flights, too few to score	56 flights, too few to score	67.7% on time128 flights	67 flights, too few to score
7 PM–8 PM	72.5% on time192 flights	67.8% on time146 flights	78.2% on time147 flights	65.9% on time177 flights	69.8% on time186 flights	79 flights, too few to score	63.8% on time152 flights
8 PM–9 PM	83 flights, too few to score	49 flights, too few to score	48 flights, too few to score	83 flights, too few to score	78 flights, too few to score	50 flights, too few to score	79 flights, too few to score
9 PM–10 PM	69 flights, too few to score	56 flights, too few to score	54 flights, too few to score	72 flights, too few to score	72 flights, too few to score	77 flights, too few to score	70 flights, too few to score
10 PM–11 PM	70.2% on time167 flights	81.0% on time155 flights	72.6% on time158 flights	65.8% on time164 flights	73.9% on time167 flights	79.5% on time153 flights	63.8% on time165 flights

By departure window

5–9 AM83.8%

9 AM–12 PM82.9%

12–3 PM77.1%

3–6 PM69.9%

6–9 PM66.8%

9 PM–5 AM68.2%

By departure hour

12 AM

3 AM

6 AM

9 AM

12 PM

3 PM

6 PM

9 PM

Why ATL → IAH runs late

July 2023 – July 2026

The airline36.8%

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

Late-arriving aircraft32.9%

the inbound aircraft was late, so this flight started late

Air traffic control25.8%

airspace and airport capacity, including weather-driven flow control

Weather4.5%

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 ATL → IAH. Only delays of 15 minutes or more are attributed.

How this route holds up in bad weather

July 2023 – July 2026

Bad weather raises cancellations by a similar amount at both ends of ATL to IAH: 3.3 times the normal rate at ATL and 3.4 times at IAH. Cancelled in bad weather against normal hours: ATL 3.4% against 1.0%, IAH 4.1% against 1.2%. Flights that did leave IAH in bad weather arrived on time 63.8% of the time, against 78.6% in normal hours.

Bad weather and normal hours at the airports

Scheduled departures, July 2023 – July 2026

Departures from ATL and IAH in hours of bad weather and in normal hours
Departures from	ATL	IAH
Cancelled in bad weather	3.4%	4.1%
Cancelled in normal hours	1.0%	1.2%
Arrived on time, bad weather	66.5%	63.8%
Arrived on time, normal hours	80.2%	78.6%
Departures in bad weather	105,854	28,922

Of the carriers on this route, United Airlines (2.6% cancelled against 3.6% for the other carriers at ATL) cancelled the fewest departures from ATL in bad weather and Frontier Airlines (5.0% cancelled against 3.8% for the other carriers at ATL) the most.

This route’s airlines in bad weather at ATL

All departures from ATL

Cancellation rates in bad weather at ATL for the airlines that fly ATL to IAH, against the other carriers at ATL in the same months
Airline	Bad-weather departures	Cancelled	Other carriers
United Airlines	2,567	2.6%below the others	3.6%
Delta Air Lines	73,919	3.5%about level	3.6%
Spirit Airlines	2,965	3.9%above the others	3.2%
Frontier Airlines	4,928	5.0%above the others	3.8%

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

Weather source and limits. In full: ATL (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
Delta Air Lines	7,359	76.1%	1.49%	-2 min	7.3%
United Airlines	3,479	81.2%	1.26%	-7 min	7.1%
Frontier Airlines	1,728	67.9%	2.26%	-2 min	15.6%
Spirit Airlines	1,669	67.0%	2.70%	0 min	13.3%

Delta Air Lines flew 51.7% of the 14,235 flights listed. Spirit Airlines cancelled 2.70% of its flights here against 1.26% for United Airlines.

United Airlines arrived on time 14.2 percentage points more often than Spirit 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
DL1601 Delta Air Lines	10:40 PM	1,119	71.6%
DL1284 Delta Air Lines	7:59 PM	998	71.3%
DL1585 Delta Air Lines	7:05 AM	942	84.9%
DL1223 Delta Air Lines	4:25 PM	740	73.6%
F91403 Frontier Airlines	6:00 AM	712	75.4%

DL1585 (7:05 AM) arrived on time 84.9% of the time, 13.6 points more often than DL1284 (7:59 PM) at 71.3%.

Weekly and seasonal patterns

By day of week

Mon74.3%

Tue77.5%

Wed78.5%

Thu74.7%

Fri74.5%

Sat77.2%

Sun71.8%

Wednesday is historically the most reliable day and Sunday the least, a gap of 6.7 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 20.3 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 76.4% against 73.7% in the 12 months before — improving by 2.7 percentage points.

Data and methodology

Calculated by FlyerIntel from 14,365 ATL → 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

ATL airport IAH airport Return direction IAH → ATL

ATL→IAH

Right now

Route reliability

Why ATL → 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 ATL → 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 ATL

Airlines on this route

Flights on this route

Weekly and seasonal patterns

By day of week

By month

Reliability over time

Data and methodology