FlightRecord

Washington Dulles International Airport (IAD): Delays & On-Time Performance

Data through May 2026

Washington Dulles International Airport (IAD) is a tale of two seasons: departures ran 91% on-time in October 2024 but sank to 71% in July 2025. Across the year it averages 83% against a national 78%, over roughly 160 departures a day to 79 destinations.

Departures on-time
83%
left <15 min late
Avg dep delay
15 min
Arrivals on-time
83%
Cancelled
1.2%
Destinations
79
nonstop
Airlines
11

Monthly on-time trend

Monthly departure on-time percentage at IAD50%75%100%June 2024: 82% on-time (4,517 flights)82Jun 2024July 2024: 76% on-time (4,692 flights)76August 2024: 78% on-time (4,584 flights)78September 2024: 89% on-time (4,313 flights)89Sep 2024October 2024: 91% on-time (4,662 flights)91November 2024: 89% on-time (4,666 flights)89December 2024: 81% on-time (4,479 flights)81Dec 2024January 2025: 81% on-time (4,008 flights)81February 2025: 86% on-time (3,742 flights)86March 2025: 86% on-time (4,615 flights)86Mar 2025April 2025: 87% on-time (5,036 flights)87May 2025: 81% on-time (5,491 flights)81June 2025: 74% on-time (5,271 flights)74Jun 2025July 2025: 71% on-time (5,248 flights)71August 2025: 83% on-time (5,201 flights)83September 2025: 89% on-time (4,815 flights)89Sep 2025October 2025: 88% on-time (4,854 flights)88November 2025: 85% on-time (4,589 flights)85December 2025: 79% on-time (4,676 flights)79Dec 2025January 2026: 84% on-time (4,248 flights)84February 2026: 85% on-time (4,037 flights)85March 2026: 80% on-time (4,983 flights)80Mar 2026April 2026: 89% on-time (4,843 flights)89May 2026: 87% on-time (5,474 flights)87

Best time of day to depart from IAD

On-time percentage by scheduled departure hour at IAD5 a.m.: 91% on-time (587 flights)56 a.m.: 92% on-time (6,526 flights)67 a.m.: 87% on-time (3,628 flights)78 a.m.: 91% on-time (21,581 flights)89 a.m.: 90% on-time (4,928 flights)910 a.m.: 86% on-time (1,640 flights)1011 a.m.: 85% on-time (1,062 flights)1112 p.m.: 87% on-time (15,405 flights)121 p.m.: 86% on-time (4,495 flights)132 p.m.: 79% on-time (1,587 flights)143 p.m.: 81% on-time (3,469 flights)154 p.m.: 76% on-time (2,349 flights)165 p.m.: 76% on-time (24,870 flights)176 p.m.: 70% on-time (4,037 flights)187 p.m.: 74% on-time (2,822 flights)198 p.m.: 70% on-time (1,189 flights)209 p.m.: 64% on-time (197 flights)2110 p.m.: 80% on-time (12,668 flights)22scheduled departure hour

Busiest routes from IAD

RouteFlights/12moOn-timeAvg delay
IAD → ATL3,94679%19 min
IAD → DEN3,62481%13 min
IAD → SFO2,82880%15 min
IAD → LAX2,42783%13 min
IAD → MCO2,20479%17 min
IAD → CLT2,02482%16 min
IAD → ORD2,02477%16 min
IAD → SEA1,92679%14 min

Most reliable routes

  1. IAD → RIC92%
  2. IAD → CHS89%
  3. IAD → SDF88%
  4. IAD → STT87%
  5. IAD → PWM87%

Most delay-prone routes

  1. IAD → EYW69%
  2. IAD → EWR70%
  3. IAD → LGA74%
  4. IAD → ROC74%
  5. IAD → ANC75%

Airline performance at IAD

AirlineOn-time departuresAvg delayFlights
Endeavor Air90%8 min151
Republic Airways86%12 min17,663
United Airlines84%13 min69,994
PSA Airlines81%19 min2,753
Delta Air Lines80%19 min6,136
SkyWest Airlines80%27 min5,399
Alaska Airlines77%14 min3,447
American Airlines77%23 min2,034
Southwest Airlines75%14 min2,455
Allegiant Air73%32 min865
Frontier Airlines71%31 min2,147

Frequently asked questions

How often are flights delayed at IAD?
17% of departures from Washington Dulles International Airport left 15+ minutes late between 2024-06 and 2026-05, with an average departure delay of 15 minutes. The national on-time average over the same period was 78%.
What is the best time of day to depart from IAD?
Flights scheduled around 6 a.m. depart on time 92% of the time at IAD, versus 64% around 9 p.m.. Booking before noon is the usual rule of thumb here.
What is the worst month for delays at IAD?
In this dataset, July 2025 was the weakest month at IAD, with 71% of departures on time.
How often are flights cancelled at IAD?
1.2% of scheduled departures from IAD were cancelled in this period, compared with a national rate of 1.6%.

Popular route pages from this airport

Based on 113,044 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.