Route reliability record
CMH→IAD
Columbus to Washington
- Flights
- 935
- Period
- September 2025 to August 2026
- Distance
- 299 mi
- Carriers
- 2
This route 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 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 935 CMH to IAD flights, of which Republic Airways flew 527 at 89.7% on time.
Best time to fly CMH to IAD: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 94.5% of the time and Saturday flights 91.9%, against 84.9% for the route overall.
Set against the rest of the country, this route's record is 8 points better than the US average of 77.3%. That gap is worth roughly 76 fewer late arrivals for every thousand flights.
Key figures
On time
84.9%
Arrivals under 15 minutes late, of 927 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.89%
Best carrier
Republic
89.7% on time across 527 flights
These figures cover 935 flights between September 2025 and August 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on CMH to IAD
The choice of carrier is not cosmetic here. Republic Airways arrives on time 89.7% of the time; United Airlines manages 78.8%. Sample sizes sit next to every figure, because a two-point gap across 408 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 527 | 89.7% | 61 min | 0.95% | A+ |
| United Airlines | 408 | 78.8% | 91 min | 0.74% | B+ |
Republic leads United by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on CMH to IAD
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Columbus 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. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. CMH → IADColumbus to Washington | Republic Airways | 88.8% | 89.7% | 0.95% | 5am–8am, Sat | YX 3430 06:00 |
| 2. CMH → BWIColumbus to Baltimore | Southwest Airlines | 85.9% | 87.2% | 1.53% | 5am–8am, Tue | — |
| 3. CMH → IADColumbus to Washington | United Airlines | 78.2% | 78.8% | 0.74% | 8am–11am, Wed | — |
| 4. CMH → DCAColumbus to Washington | PSA Airlines | 65.3% | 70.6% | 7.51% | 5am–8am, Sat | — |
| 5. CMH → DCAColumbus to Washington | Republic Airways | 64.7% | 67.3% | 3.84% | 8am–11am, Sat | — |
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 22 points, against 11 points between the best and worst carrier.
- 5am–8am312 flights94.5%
- 8am–11am175 flights87.2%
- 11am–2pm22 flights—
- 2pm–5pm188 flights72.9%
- 5pm–8pm74 flights77.0%
- 8pm–5am164 flights79.6%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.5% of the time, against 72.9% for the afternoon window. That is 22 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 312 flights scheduled in it.
Explore
Filter CMH 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 CMH to IAD, the best departure window is 5am–8am at 94.5% on time and the worst is 2pm–5pm at 72.9%, a wide gap of 21.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.5%
- 8–11am87.2%
- 11am–2pm—
- 2–5pm72.9%
- 5–8pm77.0%
- 8pm–5am79.6%
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 20 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.
December is the weak month at 75.0% on time, against 95.3% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. September was the busiest month here, with 136 flights.
Across the week, Saturday is the strongest day at 91.9% on time and Monday the weakest at 74.3%, a spread of 18 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 44% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 37%Carrier
- 16%National Airspace System
- 3%Extreme weather
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 14 to one. The split is drawn from 11,127 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,072 of the 11,000 delay minutes reported here.
Cancellations are rare at 0.86%, 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
5.7% of arrivals land an hour or more late, close to the national 8.3%, so 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.
At 299 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 82.1% on time across 936 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 935 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in IAD after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 935 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 84.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 927 completed flights over 12 months sit behind that.
Common questions
CMH to IAD questions
How often is CMH to IAD delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 15.1% of the 935 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on CMH to IAD?
Republic Airways leads at 89.7% on time across 527 flights. United Airlines is at the other end on 78.8%, a gap of 11 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on CMH to IAD?
The 5am–8am departure window is the strongest at 94.5% on time. The 2pm–5pm window is the weakest at 72.9%, 22 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 December delays on CMH to IAD?
December is the weakest month at 75.0% on time, compared with 95.3% in April. Across the year that is 20 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 CMH — the return legseparate record
- John Glenn Columbus International (CMH) delay statistics
- Washington Dulles International (IAD) delay statistics
- Republic Airways on CMH to IAD89.7%
- United Airlines on CMH to IAD78.8%
- CMH to ORD, a related route75.4%
- ATL to IAD, a related route76.4%
- CMH to ATL, a related route84.8%
- Republic Airways on-time record89.7%
- United Airlines on-time record78.8%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. CMH to IAD and IAD to CMH are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.