Route reliability record

ATL→HOU

Atlanta to Houston

Flights: 2,915
Period: July 2025 to June 2026
Distance: 696 mi
Carriers: 2

This route lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrive 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 2,915 flights, of which Delta Air Lines flew 1,416 at 81.2% on time.

The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

80.5%

Arrivals under 15 minutes late, of 2,874 completed flights

Avg delay

57 min

Across delayed arrivals only, not all flights

Cancelled

1.20%

National rate is 1.81%

Best carrier

Delta

81.2% on time across 1,416 flights

These figures cover 2,915 flights between July 2025 and June 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Which airline is most reliable on ATL to HOU

The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on ATL to HOU
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,416	81.2%	56 min	1.77%	B
Southwest Airlines	1,499	79.9%	58 min	0.67%	B+

No carrier stands out. Delta tops the table at 81.2%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

The best time of day to leave

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

5am–8am326 flights93.2%
8am–11am539 flights88.4%
11am–2pm611 flights86.6%
2pm–5pm602 flights78.3%
5pm–8pm366 flights64.1%
8pm–5am471 flights70.4%

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 93.2% 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 11am–2pm window is the busiest, with 611 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.February best, July worst

July is the worst month at 72.3% on time, 17 points below February, the best at 88.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 275 flights.

Across the week, Wednesday is the strongest day at 85.5% on time and Friday the weakest at 77.8%. 8 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 32,000 reported delay minutes.

Carrier
40%
Late-arriving aircraft
40%
National Airspace System
16%
Extreme weather
3%
Security
0%

40% 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 32,000 reported delay minutes here, that single category outweighs weather by 12 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 31,991 reported delay minutes.

The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 13,000 of the 32,000 delay minutes reported here.

Cancellations sit at 1.20% against a national 1.81%, which is ordinary. Diversions add another 0.21%.

Connections and stage length

What a delay here actually costs

5.9% of arrivals land an hour or more late, close to the national 8.1%. 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 are the about an hour kind, which a normal layover absorbs.

The 696 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 79.8% on time across 2,917 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 2,915 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 88.9% on time and July 72.3%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 2,874 completed flights over 12 months sit behind that.

Common questions

ATL to HOU questions

How often is ATL to HOU delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.5% of the 2,915 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on ATL to HOU?

Delta Air Lines leads at 81.2% on time across 1,416 flights. Southwest Airlines is at the other end on 79.9%, a gap of about a point. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on ATL to HOU?

The 5am–8am departure window is the strongest at 93.2% on time. The 5pm–8pm window is the weakest at 64.1%, 29 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on ATL to HOU?

July is the weakest month at 72.3% on time, compared with 88.9% in February. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. ATL to HOU and HOU to ATL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures