Route reliability record

RDU→ATL

Raleigh to Atlanta

Flights: 4,613
Period: June 2025 to May 2026
Distance: 356 mi
Carriers: 3

This route earns a A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.4%. When something does go wrong the average delay runs an hour and a half. That rests on 4,613 flights, of which Delta Air Lines flew 3,801 at 88.4% on time.

Set against the rest of the country, this route's record is 9 points better than the US average of 77.4%. That gap is worth roughly 92 fewer late arrivals for every thousand flights.

On time

86.6%

Arrivals under 15 minutes late, of 4,534 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

1.60%

National rate is 1.80%

Best carrier

Delta

88.4% on time across 3,801 flights

These figures cover 4,613 flights between June 2025 and May 2026. The median arrival is 11 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 RDU to ATL

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 88.4% of the time; Frontier Airlines manages 71.6%. Sample sizes sit next to every figure, because a two-point gap across 535 flights means less than a ten-point one.

On-time performance by carrier on RDU to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlinesthin sample	277	89.8%	74 min	0.72%	A+
Delta Air Lines	3,801	88.4%	81 min	1.42%	A
Frontier Airlines	535	71.6%	94 min	3.36%	C−

Frontier Airlines cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

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 14 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am1,215 flights89.3%
8am–11am769 flights91.8%
11am–2pm966 flights89.0%
2pm–5pm732 flights83.8%
5pm–8pm745 flights78.3%
8pm–5am186 flights77.9%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 91.8% of the time, against 77.9% for the overnight window. That is 14 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.

Across the year

When delays peak on this route

This route's year swings by 18 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, June worst

June is the worst month at 77.6% on time, 18 points below September, the best at 95.5%. 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.

Across the week, Wednesday is the strongest day at 90.5% on time and Sunday the weakest at 82.1%. 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 51,000 reported delay minutes.

Late-arriving aircraft
38%
Carrier
35%
National Airspace System
27%
Extreme weather
1%

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 51,000 reported delay minutes here, that single category outweighs weather by 38 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 largest share of delay minutes, 35%, 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 18,000 of the 51,000 delay minutes reported here.

Cancellations sit at 1.60% against a national 1.80%, which is ordinary. Diversions add another 0.11%.

Connections and stage length

What a delay here actually costs

5.2% of arrivals land an hour or more late, close to the national 8.2%. 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 an hour and a half 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 8am–11am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 79.3% on time across 4,613 flights, 7 points below 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 4,613 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 95.5% on time and June 77.6%, a swing of 18 points. If the dates move at all, move them out of June before you think about anything else.

Common questions

RDU to ATL questions

How often is RDU to ATL delayed?

About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.4% of the 4,613 flights in this analysis, against 22.6% nationally. Delayed flights are late by an hour and a half on average.

Which airline is most reliable on RDU to ATL?

Delta Air Lines leads at 88.4% on time across 3,801 flights. Frontier Airlines is at the other end on 71.6%, a gap of 17 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 RDU to ATL?

The 8am–11am departure window is the strongest at 91.8% on time. The 8pm–5am window is the weakest at 77.9%, 14 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 June delays on RDU to ATL?

June is the weakest month at 77.6% on time, compared with 95.5% in September. Across the year that is 18 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. RDU to ATL and ATL to RDU 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, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures