Route reliability record
RDU→MIA
Raleigh to Miami
- Flights
- 2,350
- Period
- July 2025 to June 2026
- Distance
- 700 mi
- Carriers
- 5
This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrive 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 2,350 flights, with a median arrival 7 minutes early.
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.
Key figures
On time
76.8%
Arrivals under 15 minutes late, of 2,303 completed flights
Avg delay
95 min
Across delayed arrivals only, not all flights
Cancelled
1.83%
National rate is 1.81%
Best carrier
American
77.2% on time across 1,705 flights
These figures cover 2,350 flights between July 2025 and June 2026. Beyond the headline rate, 10.8% 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
Which airline is most reliable on RDU to MIA
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Linesthin sample | 360 | 80.5% | 82 min | 1.67% | B |
| American Airlines | 1,705 | 77.2% | 102 min | 1.64% | B |
| Envoy Airthin sample | 70 | 72.5% | 55 min | 1.43% | C |
| Frontier Airlinesthin sample | 185 | 70.2% | 89 min | 3.78% | C− |
| Republic Airwaysthin sample | 30 | 58.6% | 49 min | 3.33% | D− |
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 30 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am442 flights92.3%
- 8am–11am711 flights82.5%
- 11am–2pm410 flights76.0%
- 2pm–5pm76 flights67.1%
- 5pm–8pm569 flights61.9%
- 8pm–5am142 flights66.9%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.9% on time, against 92.3% 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 8am–11am window is the busiest, with 711 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 14 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.
July is the worst month at 68.8% on time, 14 points below June, the best at 82.8%. 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 224 flights.
Across the week, Thursday is the strongest day at 82.4% on time and Sunday the weakest at 71.7%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 51,000 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.
- 46%Late-arriving aircraft
- 41%Carrier
- 11%National Airspace System
- 1%Extreme weather
- 0%Security
46% 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 36 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 50,837 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 21,000 of the 51,000 delay minutes reported here.
Cancellations sit at 1.83% against a national 1.81%, which is ordinary. Diversions add another 0.17%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.8% 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 71.4% on time across 2,347 flights, 5 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 5 points of difference.
The sample behind these figures is 2,350 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. June runs 82.8% on time and July 68.8%, a swing of 14 points. If the dates move at all, move them out of July before you think about anything else. 2,303 completed flights over 12 months sit behind that.
Common questions
RDU to MIA questions
How often is RDU to MIA delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.2% of the 2,350 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is RDU to MIA compared with the rest of the country?
76.8% of flights arrive on time here against a national 77.6%, a difference of about a point against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on RDU to MIA?
The 5am–8am departure window is the strongest at 92.3% on time. The 5pm–8pm window is the weakest at 61.9%, 30 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 RDU to MIA?
July is the weakest month at 68.8% on time, compared with 82.8% in June. Across the year that is 14 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- MIA to RDU — the return legseparate record
- Raleigh-Durham International (RDU) delay statistics
- Miami International (MIA) delay statistics
- Delta Air Lines on-time record80.5%
- American Airlines on-time record77.2%
- Envoy Air on-time record72.5%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. RDU to MIA and MIA 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.