Airport month record

RDUSEP

Raleigh-Durham International in September 2025

Departures: 4,484
Month: September 2025
National, same month: 83.4%
Carriers: 10

Historical statistics for September 2025, not live status or a forecast for this year’s September. For today’s conditions at RDU, see live FAA status.

RDU in September earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it about a point better than the national rate of 83.4%. When something does go wrong the average delay runs a little over an hour. That rests on 4,484 flights, of which Delta Air Lines flew 1,005 at 90.1% on time.

Delta Air Lines is the most reliable of the five carriers covered here at 90.1% on time across 1,005 flights.

On time

84.6%

Arrivals under 15 minutes late, of 4,455 completed departures

Avg delay

81 min

Across delayed arrivals only, not all flights

Cancelled

0.51%

Nationally in September: 0.51%

Whole year

79.0%

RDU across all twelve months

These figures cover 4,484 departures from Raleigh-Durham International in September 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

September next to RDU's other months

Against RDU's own year, September ran 6 points better than the twelve-month rate of 79.0%, which makes it the best of the twelve months in the data. Cancellations were unusually low for RDU in September, at 0.51% against 2.28% across the year. Either side of it, August ran 78.7% on time and October 79.0%, so a trip moved by a few weeks would have landed in a worse stretch.

RDU month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	4,907	71.6%	97 min	3.81%	C−
August 2025	4,640	78.7%	82 min	1.34%	B
September 2025 (this page)	4,484	84.6%	81 min	0.51%	B+
October 2025	4,929	79.0%	67 min	0.63%	B+
November 2025	4,796	80.4%	80 min	2.04%	B
December 2025	4,803	73.5%	76 min	1.71%	C
January 2026	4,163	81.0%	76 min	8.17%	B−
February 2026	3,954	82.1%	76 min	3.69%	B−
March 2026	4,658	77.2%	83 min	2.81%	B
April 2026	4,748	82.4%	70 min	0.63%	B+
May 2026	4,884	81.4%	67 min	0.86%	B+
June 2026	4,615	77.2%	84 min	2.08%	B

Departure window

The best time of day to leave RDU in September

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am1,056 flights95.1%
8am–11am745 flights91.0%
11am–2pm814 flights85.3%
2pm–5pm747 flights77.6%
5pm–8pm901 flights76.9%
8pm–5am221 flights65.8%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.1% of the time, against 65.8% for the overnight window. That is 29 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 1,056 flights scheduled in it.

Across the week, Saturday is the strongest day at 87.7% on time and Thursday the weakest at 78.6%. 9 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at RDU in September

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 90.1% of the time; Republic Airways manages 81.4%. Sample sizes sit next to every figure, because a two-point gap across 629 flights means less than a ten-point one.

Carriers at RDU in September 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,005	90.1%	84 min	0.30%	A+
American Airlines	849	83.3%	113 min	0.71%	B+
Southwest Airlines	688	88.5%	56 min	0.00%	A+
Republic Airways	629	81.4%	77 min	0.79%	B+
United Airlines	535	88.0%	89 min	0.37%	A+
Frontier Airlinesthin sample	334	80.1%	55 min	0.90%	B+
JetBlue Airwaysthin sample	208	71.4%	58 min	0.96%	C+
PSA Airlinesthin sample	116	65.2%	89 min	0.86%	C+
Spirit Airlinesthin sample	52	76.0%	73 min	1.92%	B
Alaska Airlinesthin sample	47	91.1%	35 min	0.00%	A+

Delta leads Republic by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Route by route

Busiest routes out of RDU in September

Routes from RDU in September 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
RDU to ATL · Atlanta	401	95.5%	95 min	0.00%	A+
RDU to ORD · Chicagothin sample	266	82.7%	110 min	0.00%	B+
RDU to BOS · Bostonthin sample	256	66.4%	83 min	1.17%	C
RDU to LGA · New Yorkthin sample	255	77.7%	79 min	1.57%	B
RDU to CLT · Charlottethin sample	245	85.7%	95 min	0.00%	A+
RDU to PHL · Philadelphiathin sample	207	78.2%	107 min	0.48%	B+
RDU to MCO · Orlandothin sample	204	88.2%	36 min	0.49%	A+
RDU to JFK · New Yorkthin sample	197	81.5%	87 min	1.02%	B
RDU to BNA · Nashvillethin sample	183	86.9%	68 min	0.00%	A+
RDU to MIA · Miamithin sample	180	82.7%	86 min	0.00%	B+
RDU to DFW · Dallas-Fort Worththin sample	179	81.5%	112 min	2.79%	B
RDU to DCA · Washingtonthin sample	172	67.1%	84 min	1.16%	C
RDU to BWI · Baltimorethin sample	141	92.1%	52 min	0.00%	A+
RDU to EWR · Newarkthin sample	141	81.2%	78 min	1.42%	B
RDU to IAD · Washingtonthin sample	139	92.8%	79 min	0.72%	A+
RDU to DEN · Denverthin sample	133	80.5%	58 min	0.00%	B+
RDU to DTW · Detroitthin sample	130	93.1%	62 min	0.00%	A+
RDU to MSP · Minneapolisthin sample	107	89.7%	105 min	0.00%	A+
RDU to MDW · Chicagothin sample	90	88.9%	61 min	0.00%	A+
RDU to TPA · Tampathin sample	89	95.5%	49 min	0.00%	A+
RDU to FLL · Fort Lauderdalethin sample	81	85.0%	34 min	1.23%	A
RDU to SEA · Seattlethin sample	77	93.3%	32 min	0.00%	A+
RDU to SFO · San Franciscothin sample	77	90.9%	48 min	0.00%	A+
RDU to IAH · Houstonthin sample	74	93.2%	68 min	0.00%	A+
RDU to PIT · Pittsburghthin sample	60	84.7%	60 min	1.67%	B

Delay causes

What held RDU up in September

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.

Late-arriving aircraft
37%
Carrier
32%
National Airspace System
26%
Extreme weather
5%

37% 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 8 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 55,118 reported delay minutes.

Cancellations are rare at 0.51%, below the national 0.51% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

5.3% of arrivals land an hour or more late, close to the national 5.4%. 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 last a little over an hour, which a normal layover absorbs.

What to do with this

Flying from RDU in September

For a September trip through RDU: this is one of the better months to be flying from here, 84.6% on time with 0.51% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.

Raleigh-Durham International (RDU), the whole year
RDU in July71.6%
RDU in August78.7%
RDU in October79.0%
RDU in November80.4%
RDU in December73.5%
RDU in January81.0%
RDU in February82.1%
RDU in March77.2%
RDU in April82.4%
RDU in May81.4%
RDU in June77.2%

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