Route reliability record
CHS→IAD
Charleston to Washington
- Flights
- 759
- Period
- July 2025 to June 2026
- Distance
- 442 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 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 759 CHS to IAD flights, with a median arrival 9 minutes early.
Best time to fly CHS to IAD: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 94.3% of the time and Wednesday flights 88.1%, against 84.8% for the route overall.
Set against the rest of the country, this route's record is 7 points better than the US average of 77.6%. That gap is worth roughly 72 fewer late arrivals for every thousand flights.
Key figures
On time
84.8%
Arrivals under 15 minutes late, of 748 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
1.32%
National rate is 1.81%
Best carrier
United
86.6% on time across 459 flights
These figures cover 759 flights between July 2025 and June 2026. The median arrival is 9 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.
Carrier by carrier
Which airline is most reliable on CHS 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 | 459 | 86.6% | 97 min | 0.65% | A+ |
| Republic Airwaysthin sample | 300 | 81.8% | 77 min | 2.33% | B |
Best ways to make this trip
The most reliable ways to fly Charleston 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. CHS → IADCharleston to Washington | United Airlines | 86.0% | 86.6% | 0.65% | 8am–11am, Wed | — |
| 2. CHS → BWICharleston to Baltimore | Southwest Airlines | 80.5% | 81.9% | 1.71% | 5am–8am, Wed (route) | — |
| 3. CHS → DCACharleston to Washington | American Airlines | 75.2% | 76.9% | 2.19% | 5am–8am, Sat | — |
| 4. CHS → DCACharleston to Washington | Republic Airways | 74.1% | 77.4% | 4.27% | 5am–8am, Sat | — |
| 5. CHS → DCACharleston to Washington | PSA Airlines | 63.2% | 67.9% | 6.86% | 5am–8am, 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 19 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am35 flights94.3%
- 8am–11am281 flights94.0%
- 11am–2pm—
- 2pm–5pm360 flights78.6%
- 5pm–8pm83 flights75.3%
- 8pm–5am—
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 94.3% of the time, against 75.3% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 360 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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 71.9% on time, against 96.0% in September. 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. March was the busiest month here, with 90 flights.
Across the week, Wednesday is the strongest day at 88.1% on time and Sunday the weakest at 76.9%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 72% of the 10,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 72%Late-arriving aircraft
- 17%National Airspace System
- 10%Carrier
- 1%Extreme weather
72% 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 10,000 reported delay minutes here, that single category outweighs weather by 58 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 10,018 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 94.3% on time here.
Cancellations sit at 1.32% against a national 1.81%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here actually costs
7.5% of arrivals land an hour or more late, close to the national 8.1%. 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 an hour and a half, which a normal layover absorbs.
At 442 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 86.8% on time across 761 flights, within 2 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. 759 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. 759 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 84.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 748 completed flights over 12 months sit behind that.
Common questions
CHS to IAD questions
How often is CHS 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 15.2% of the 759 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is CHS to IAD compared with the rest of the country?
84.8% of flights arrive on time here against a national 77.6%, a difference of 7 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on CHS to IAD?
The 5am–8am departure window is the strongest at 94.3% on time. The 5pm–8pm window is the weakest at 75.3%, 19 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 CHS to IAD?
December is the weakest month at 71.9% on time, compared with 96.0% in September. Across the year that is 24 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 CHS — the return legseparate record
- Washington Dulles International (IAD) delay statistics
- United Airlines on CHS to IAD86.6%
- Republic Airways on CHS to IAD81.8%
- CHS to ATL, a related route90.2%
- ATL to IAD, a related route76.5%
- CHS to CLT, a related route83.8%
- United Airlines on-time record86.6%
- Republic Airways on-time record81.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. CHS to IAD and IAD to CHS 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.