Carrier route record

DLMIA→RDU

Delta Air Lines · Miami to Raleigh

Flights: 360
Period: July 2025 to June 2026
Share of route: 15%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on MIA to RDU draws a D. About one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 360 flights, with a median arrival 1 minute early.

The national on-time rate over the same period is 77.6%, so Delta on MIA to RDU runs 13 points behind the country as a whole. Across a thousand flights that is about 129 extra late arrivals.

On time

64.7%

Arrivals under 15 minutes late, of 351 completed flights

Avg delay

95 min

Across delayed arrivals only, not all flights

Cancelled

2.50%

National rate is 1.81%

Whole route

71.4%

Every carrier on MIA to RDU, 2,347 flights

These figures cover 360 flights between July 2025 and June 2026. Beyond the headline rate, 17.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Delta against every carrier on MIA to RDU

Delta flew 360 of the 2,347 flights on MIA to RDU, about 15% of it. Its 64.7% on time is 7 points worse than the route as a whole, which runs 71.4%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Envoy at 88.7% to Republic at 64.3%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on MIA to RDU
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	72	88.7%	42 min	1.39%	A
Frontier Airlinesthin sample	185	78.6%	70 min	1.62%	B
American Airlines	1,700	71.4%	72 min	1.47%	C
Delta Air Lines (this page)thin sample	360	64.7%	95 min	2.50%	D
Republic Airwaysthin sample	30	64.3%	80 min	6.67%	D−

Flight by flight

Delta flight numbers on MIA to RDU

DL 299218:4064.7% · 360 flights

Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 360 flights.

There are not enough flights in each departure window to split Delta's MIA to RDU record by time of day without the percentages moving on noise. The headline rate of 64.7% is the reliable figure here.

Across the year

Delta on MIA to RDU through the year

Jul–Sep 202592 flights53.9%
Oct–Dec 202587 flights75.9%
Jan–Mar 202690 flights65.5%
Apr–Jun 202691 flights63.6%

Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 64.7% on time across 360 flights.

Delta on MIA to RDU did not run the same all year. Its best quarter was Oct–Dec 2025 at 75.9% on time and its weakest Jul–Sep 2025 at 53.9%, a swing of 22 points on roughly 90 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Monday is the strongest day at 78.0% on time and Sunday the weakest at 48.0%. 30 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 71% of the 12,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
71%
Carrier
11%
Extreme weather
10%
National Airspace System
8%

71% 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 12,000 reported delay minutes here, that single category outweighs weather by 7 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 11,756 reported delay minutes.

Cancellations run at 2.50%, against 1.81% nationally. That is about one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 17.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 700 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 is a different operation and performs like one: it runs 80.5% on time across 360 flights, 16 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 16 points of difference.

One caution: this is a thin sample. 360 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking Delta on MIA to RDU

Put together: treat all of this as provisional. 360 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 64.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 351 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures