Route reliability record
ORD→IAD
Chicago to Washington
- Flights
- 2,103
- Period
- September 2025 to August 2026
- Distance
- 588 mi
- Carriers
- 1
This route sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, about a point worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,103 ORD to IAD flights, with a median arrival 3 minutes early.
Best time to fly ORD to IAD: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 98.2% of the time and Tuesday flights 80.6%, against 75.9% for the route overall.
The US average over the same twelve months is 77.3%, 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
75.9%
Arrivals under 15 minutes late, of 2,084 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
0.76%
National rate is 1.89%
Best carrier
United
75.9% on time across 2,103 flights
These figures cover 2,103 flights between September 2025 and August 2026. Beyond the headline rate, 9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on ORD to IAD
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 |
|---|---|---|---|---|---|
| United Airlines | 2,103 | 75.9% | 78 min | 0.76% | B+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Best ways to make this trip
The most reliable ways to fly Chicago to Washington
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MDW → BWIChicago to Baltimore | Southwest Airlines | 75.7% | 77.8% | 2.74% | 5am–8am, Sat (route) | — |
| 2. ORD → IADChicago to Washington | United Airlines | 75.3% | 75.9% | 0.76% | 5am–8am, Tue | — |
| 3. ORD → BWIChicago to Baltimore | Envoy Air | 74.4% | 77.3% | 3.80% | 5am–8am, Sat | — |
| 4. ORD → BWIChicago to Baltimore | United Airlines | 69.2% | 70.3% | 1.59% | 5am–8am, Tue | — |
| 5. ORD → DCAChicago to Washington | United Airlines | 68.6% | 70.1% | 2.14% | 5am–8am, Sat | UA 1077 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 38 points, against half a point between the best and worst carrier.
- 5am–8am115 flights98.2%
- 8am–11am429 flights86.9%
- 11am–2pm492 flights79.1%
- 2pm–5pm419 flights71.5%
- 5pm–8pm364 flights60.7%
- 8pm–5am284 flights70.1%
Scale runs 50% to 100%.
The 5pm–8pm window is where this operation falls apart: 60.7% on time, against 98.2% 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 11am–2pm window is the busiest, with 492 flights scheduled in it.
Explore
Filter ORD to IAD by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ORD to IAD, the best departure window is 5am–8am at 98.2% on time and the worst is 5pm–8pm at 60.7%, a wide gap of 37.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am98.2%
- 8–11am86.9%
- 11am–2pm79.1%
- 2–5pm71.5%
- 5–8pm60.7%
- 8pm–5am70.1%
best all US flightsScale 50% to 100%.
Across the year
When delays peak on this route
This route's year swings by 17 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.
Delays peak in March, when the on-time rate falls to 66.2%. June is the strongest month at 83.3%. Moving a flexible trip across that boundary buys 17 points. August was the busiest month here, with 217 flights.
Across the week, Tuesday is the strongest day at 80.6% on time and Sunday the weakest at 69.7%, a spread of 11 points.
Delay causes
Why this route gets delayed
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 39,000 reported delay minutes.
- 38%Late-arriving aircraft
- 28%Carrier
- 24%National Airspace System
- 10%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 39,000 reported delay minutes here, that single category outweighs weather by 4 to one. The split is drawn from 39,339 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 98.2% on time here.
Cancellations are rare at 0.76%, below the national 1.89% 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.
Connections and stage length
What a delay here actually costs
9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 588 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.
The return leg runs 74.7% on time across 2,106 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,103 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.
Work out the risk of missing a connection in IAD after this flight
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 83.3% on time and March 66.2%, a swing of 17 points. If the dates move at all, move them out of March before you think about anything else. 2,084 completed flights over 12 months sit behind that.
Common questions
ORD to IAD questions
How often is ORD to IAD delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.1% of the 2,103 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is ORD to IAD compared with the rest of the country?
75.9% of flights arrive on time here against a national 77.3%, 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 ORD to IAD?
The 5am–8am departure window is the strongest at 98.2% on time. The 5pm–8pm window is the weakest at 60.7%, 38 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 March delays on ORD to IAD?
March is the weakest month at 66.2% on time, compared with 83.3% in June. Across the year that is 17 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
- IAD to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Washington Dulles International (IAD) delay statistics
- ORD to LGA, a related route66.6%
- ATL to IAD, a related route76.4%
- ORD to BOS, a related route66.6%
- United Airlines on-time record75.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. ORD to IAD and IAD to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed ORD to IAD’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.