Airport month record
IADJUL
Washington Dulles International in July 2025
- Departures
- 5,248
- Month
- July 2025
- National, same month
- 71.1%
- Carriers
- 10
Historical statistics for July 2025, not live status or a forecast for this year’s July. For today’s conditions at IAD, see live FAA status.
IAD in July sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 2 points worse than the national rate of 71.1%. The late ones land close to two hours behind schedule. That rests on 5,248 flights, of which Republic Airways flew 962 at 73.1% on time.
Key figures
On time
69.5%
Arrivals under 15 minutes late, of 5,073 completed departures
Avg delay
102 min
Across delayed arrivals only, not all flights
Cancelled
2.88%
Nationally in July: 2.45%
Whole year
81.1%
IAD across all twelve months
These figures cover 5,248 departures from Washington Dulles International in July 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
July next to IAD's other months
Against IAD's own year, July ran 12 points worse than the twelve-month rate of 81.1%, which makes it the worst of the twelve months in the data. Cancellations are where July stands out: 2.88% of scheduled departures were called off, 2.1 times the airport's rate across the year.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 (this page) | 5,248 | 69.5% | 102 min | 2.88% | C |
| August 2025 | 5,201 | 81.0% | 70 min | 0.79% | B+ |
| September 2025 | 4,815 | 86.8% | 67 min | 0.27% | A+ |
| October 2025 | 4,854 | 84.6% | 64 min | 0.27% | B+ |
| November 2025 | 4,589 | 81.8% | 71 min | 1.46% | B |
| December 2025 | 4,676 | 74.8% | 69 min | 0.71% | C+ |
| January 2026 | 4,248 | 83.0% | 82 min | 5.65% | B− |
| February 2026 | 4,037 | 83.3% | 74 min | 1.34% | B |
| March 2026 | 4,983 | 79.6% | 92 min | 1.81% | B |
| April 2026 | 4,843 | 87.2% | 71 min | 0.31% | A+ |
| May 2026 | 5,474 | 84.1% | 78 min | 0.57% | B+ |
| June 2026 | 5,053 | 78.1% | 85 min | 0.93% | B+ |
Departure window
The best time of day to leave IAD in July
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 42 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am543 flights87.1%
- 8am–11am1,336 flights85.6%
- 11am–2pm893 flights79.9%
- 2pm–5pm376 flights61.2%
- 5pm–8pm1,265 flights44.8%
- 8pm–5am835 flights61.1%
Scale runs 35% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 44.8% on time, against 87.1% 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 1,336 flights scheduled in it.
Across the week, Wednesday is the strongest day at 72.3% on time and Sunday the weakest at 66.3%. 6 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at IAD in July
The two carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 2,997 | 70.1% | 98 min | 1.17% | C |
| Republic Airways | 962 | 73.1% | 114 min | 7.69% | C− |
| Delta Air Linesthin sample | 278 | 73.4% | 111 min | 2.52% | C |
| Alaska Airlinesthin sample | 214 | 58.5% | 82 min | 0.93% | D+ |
| SkyWest Airlinesthin sample | 209 | 72.2% | 113 min | 1.44% | C |
| Frontier Airlinesthin sample | 171 | 52.5% | 118 min | 7.60% | F− |
| PSA Airlinesthin sample | 143 | 76.3% | 109 min | 5.59% | B− |
| Southwest Airlinesthin sample | 115 | 58.6% | 62 min | 3.48% | D− |
| American Airlinesthin sample | 83 | 63.6% | 103 min | 6.02% | D− |
| Allegiant Airthin sample | 76 | 61.3% | 176 min | 0.00% | D+ |
Republic Airways cancels 7.7% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Busiest routes out of IAD in July
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| IAD to DEN · Denverthin sample | 361 | 68.1% | 90 min | 1.39% | C |
| IAD to ATL · Atlantathin sample | 353 | 68.9% | 113 min | 4.25% | C− |
| IAD to SFO · San Franciscothin sample | 267 | 68.8% | 79 min | 1.12% | C |
| IAD to SEA · Seattlethin sample | 245 | 73.6% | 84 min | 0.82% | C+ |
| IAD to LAX · Los Angelesthin sample | 224 | 60.0% | 95 min | 1.79% | D |
| IAD to ORD · Chicagothin sample | 185 | 63.7% | 99 min | 1.62% | D |
| IAD to MCO · Orlandothin sample | 176 | 69.4% | 81 min | 1.70% | C |
| IAD to DFW · Dallas-Fort Worththin sample | 173 | 65.7% | 97 min | 3.47% | C− |
| IAD to TPA · Tampathin sample | 170 | 61.4% | 83 min | 1.76% | D |
| IAD to CLT · Charlottethin sample | 156 | 76.7% | 110 min | 6.41% | B− |
| IAD to IAH · Houstonthin sample | 155 | 72.1% | 86 min | 0.65% | C+ |
| IAD to PIT · Pittsburghthin sample | 129 | 76.0% | 128 min | 6.20% | B− |
| IAD to BOS · Bostonthin sample | 124 | 70.5% | 141 min | 1.61% | C |
| IAD to EWR · Newarkthin sample | 124 | 53.9% | 125 min | 6.45% | F− |
| IAD to LAS · Las Vegasthin sample | 123 | 70.7% | 77 min | 0.00% | C+ |
| IAD to PWM · Portlandthin sample | 123 | 75.0% | 150 min | 8.94% | B− |
| IAD to SAN · San Diegothin sample | 122 | 71.3% | 91 min | 0.00% | C+ |
| IAD to BNA · Nashvillethin sample | 101 | 80.6% | 80 min | 0.99% | B+ |
| IAD to AUS · Austinthin sample | 96 | 69.8% | 102 min | 0.00% | C+ |
| IAD to BTV · Burlingtonthin sample | 96 | 82.4% | 176 min | 11.46% | B− |
| IAD to IND · Indianapolisthin sample | 92 | 73.9% | 85 min | 3.26% | C− |
| IAD to PHX · Phoenixthin sample | 92 | 58.9% | 100 min | 2.17% | D |
| IAD to DTW · Detroitthin sample | 86 | 63.4% | 138 min | 4.65% | D− |
| IAD to MSP · Minneapolisthin sample | 85 | 81.0% | 123 min | 0.00% | B+ |
| IAD to CMH · Columbusthin sample | 85 | 65.8% | 118 min | 7.06% | C− |
Delay causes
What held IAD up in July
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 158,000 reported delay minutes.
- 38%Late-arriving aircraft
- 27%Carrier
- 18%National Airspace System
- 17%Extreme weather
- 0%Security
Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the comparison with the other months below is the more useful view of the risk. The national share is 7%, so this operation carries roughly 2.3 times the usual weather exposure. The split is drawn from 158,209 reported delay minutes.
Cancellations run at 2.88%, against 2.45% nationally. That is roughly one flight in 30 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.
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 15.3% of arrivals land a full hour or more behind schedule, against 12.1% 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.
What to do with this
Flying from IAD in July
For a July trip through IAD: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 87.1% on time, and with 15.3% of arrivals an hour or more late, a connection here deserves more slack than the same trip in April would.
Related
Where to go next
- Washington Dulles International (IAD), the whole year
- IAD in August81.0%
- IAD in September86.8%
- IAD in October84.6%
- IAD in November81.8%
- IAD in December74.8%
- IAD in January83.0%
- IAD in February83.3%
- IAD in March79.6%
- IAD in April87.2%
- IAD in May84.1%
- IAD in June78.1%
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.