Route reliability record

RDU→ATL

Raleigh to Atlanta

Flights: 4,618
Period: July 2025 to June 2026
Distance: 356 mi
Carriers: 3

This route earns a A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 4,618 flights, of which Delta Air Lines flew 3,800 at 89.5% on time.

Set against the rest of the country, this route's record is 10 points better than the US average of 77.6%. That gap is worth roughly 100 fewer late arrivals for every thousand flights.

On time

87.6%

Arrivals under 15 minutes late, of 4,544 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

1.52%

National rate is 1.81%

Best carrier

Delta

89.5% on time across 3,800 flights

These figures cover 4,618 flights between July 2025 and June 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 89.5% of the time; Frontier Airlines manages 73.9%. 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 RDU to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlinesthin sample	247	90.2%	68 min	0.81%	A+
Delta Air Lines	3,800	89.5%	86 min	1.37%	A
Frontier Airlines	571	73.9%	95 min	2.80%	C

The spread between Delta and Frontier is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 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 11 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am1,250 flights89.3%
8am–11am765 flights92.6%
11am–2pm988 flights88.6%
2pm–5pm712 flights84.8%
5pm–8pm707 flights82.1%
8pm–5am196 flights82.2%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 92.6% of the time, against 82.1% for the evening window. That is 11 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 1,250 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 16 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, March worst

September is the best month on the calendar at 95.5% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. October was the busiest month here, with 416 flights.

Across the week, Wednesday is the strongest day at 91.2% on time and Sunday the weakest at 83.1%. 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 49,000 reported delay minutes.

Carrier
39%
Late-arriving aircraft
35%
National Airspace System
25%
Extreme weather
1%

35% 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 49,000 reported delay minutes here, that single category outweighs weather by 35 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 49,189 reported delay minutes.

The largest share of delay minutes, 39%, 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 19,000 of the 49,000 delay minutes reported here.

Cancellations sit at 1.52% against a national 1.81%, which is ordinary. Diversions add another 0.09%.

Connections and stage length

What a delay here actually costs

Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

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 80.4% on time across 4,617 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 4,618 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 March 79.5%, a swing of 16 points. If the dates move at all, move them out of March before you think about anything else. 4,544 completed flights over 12 months sit behind that.

Common questions

RDU to ATL questions

How often is RDU to ATL delayed?

About one flight in eight arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 12.4% of the 4,618 flights in this analysis, against 22.4% 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 89.5% on time across 3,800 flights. Frontier Airlines is at the other end on 73.9%, a gap of 16 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 92.6% on time. The 5pm–8pm window is the weakest at 82.1%, 11 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 March delays on RDU to ATL?

March is the weakest month at 79.5% on time, compared with 95.5% in September. Across the year that is 16 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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures