Route reliability record

ATL→RDU

Atlanta to Raleigh

Flights: 4,617
Period: July 2025 to June 2026
Distance: 356 mi
Carriers: 3

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 4,617 flights, of which Delta Air Lines flew 3,799 at 83.2% 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

80.4%

Arrivals under 15 minutes late, of 4,548 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

1.43%

National rate is 1.81%

Best carrier

Delta

83.2% on time across 3,799 flights

These figures cover 4,617 flights between July 2025 and June 2026. The median arrival is 5 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 RDU

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 83.2% of the time; Frontier Airlines manages 60.2%. Sample sizes sit next to every figure, because a two-point gap across 571 flights means less than a ten-point one.

On-time performance by carrier on ATL to RDU
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlinesthin sample	247	83.6%	63 min	1.21%	B
Delta Air Lines	3,799	83.2%	56 min	1.24%	B
Frontier Airlines	571	60.2%	75 min	2.80%	D

The spread between Delta and Frontier is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.

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 19 points, against 23 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am357 flights89.8%
8am–11am834 flights89.6%
11am–2pm618 flights85.4%
2pm–5pm869 flights79.1%
5pm–8pm719 flights77.7%
8pm–5am1,220 flights71.3%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 89.8% of the time, against 71.3% for the overnight window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,220 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 21 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.September best, July worst

July is the worst month at 70.8% on time, 21 points below September, the best at 91.3%. 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. October was the busiest month here, with 416 flights.

Across the week, Wednesday is the strongest day at 86.6% on time and Sunday the weakest at 75.6%. 11 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 55,000 reported delay minutes.

Carrier
41%
Late-arriving aircraft
38%
National Airspace System
14%
Extreme weather
7%
Security
0%

38% 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 55,000 reported delay minutes here, that single category outweighs weather by 6 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 54,569 reported delay minutes.

The largest share of delay minutes, 41%, 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 22,000 of the 55,000 delay minutes reported here.

Cancellations sit at 1.43% against a national 1.81%, which is ordinary. Diversions add another 0.06%.

Connections and stage length

What a delay here actually costs

6.0% 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.

At 356 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 87.6% on time across 4,618 flights, 7 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 7 points of difference.

The sample behind these figures is 4,617 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. September runs 91.3% on time and July 70.8%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 4,548 completed flights over 12 months sit behind that.

Common questions

ATL to RDU questions

How often is ATL to RDU 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 19.6% of the 4,617 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 RDU?

Delta Air Lines leads at 83.2% on time across 3,799 flights. Frontier Airlines is at the other end on 60.2%, a gap of 23 points. 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 RDU?

The 5am–8am departure window is the strongest at 89.8% on time. The 8pm–5am window is the weakest at 71.3%, 19 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 RDU?

July is the weakest month at 70.8% on time, compared with 91.3% in September. Across the year that is 21 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 RDU and RDU 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