Route reliability record
BOS→CHS
Boston to Charleston
- Flights
- 1,149
- Period
- September 2025 to August 2026
- Distance
- 818 mi
- Carriers
- 3
This route lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 1,149 BOS to CHS flights, of which Delta Air Lines flew 370 at 76.2% on time.
Best time to fly BOS to CHS: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 84.0% of the time and Tuesday flights 83.3%, against 76.5% 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
76.5%
Arrivals under 15 minutes late, of 1,115 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
2.70%
National rate is 1.89%
Best carrier
Delta
76.2% on time across 370 flights
These figures cover 1,149 flights between September 2025 and August 2026. Beyond the headline rate, 9.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on BOS to CHS
The two carriers here are closely matched: about a point 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 |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 109 | 85.0% | 54 min | 1.83% | A |
| Delta Air Lines | 370 | 76.2% | 71 min | 3.24% | B− |
| JetBlue Airways | 670 | 75.3% | 71 min | 2.54% | B |
Delta Air Lines cancels 3.2% 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.
Flight by flight
Flights on BOS to CHS
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 Boston to Charleston
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BOS → CHSBoston to Charleston | Delta Air Lines | 73.7% | 76.2% | 3.24% | 11am–2pm, Tue | DL 2785 12:55 |
| 2. BOS → CHSBoston to Charleston | JetBlue Airways | 73.4% | 75.3% | 2.54% | 5am–8am, Tue | — |
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 24 points, against about a point between the best and worst carrier.
- 5am–8am148 flights84.0%
- 8am–11am325 flights81.1%
- 11am–2pm413 flights77.8%
- 2pm–5pm179 flights66.3%
- 5pm–8pm84 flights60.5%
- 8pm–5am—
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 60.5% on time, against 84.0% 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 413 flights scheduled in it.
Explore
Filter BOS to CHS 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 BOS to CHS, the best departure window is 5am–8am at 84.0% on time and the worst is 5pm–8pm at 60.5%, a wide gap of 23.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am84.0%
- 8–11am81.1%
- 11am–2pm77.8%
- 2–5pm66.3%
- 5–8pm60.5%
- 8pm–5am—
best all US flightsScale 50% to 95%. Cells under 30 flights show a dash.
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 61.6% on time, against 85.5% in May. 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. May was the busiest month here, with 124 flights.
Across the week, Tuesday is the strongest day at 83.3% on time and Thursday the weakest at 73.9%, a spread of 9 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 18,000 reported delay minutes.
- 39%Late-arriving aircraft
- 34%Carrier
- 25%National Airspace System
- 3%Extreme weather
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 18,000 reported delay minutes here, that single category outweighs weather by 14 to one. The split is drawn from 18,334 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 84.0% on time here.
Cancellations run at 2.70%, against 1.89% nationally. That is about one flight in 40 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.
Connections and stage length
What a delay here actually costs
9.9% 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 818 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 is a different operation and performs like one: it runs 69.5% on time across 1,150 flights, 7 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 7 points of difference.
The sample behind these figures is 1,149 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 CHS 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. May runs 85.5% on time and December 61.6%, a swing of 24 points. If the dates move at all, move them out of December before you think about anything else. 1,115 completed flights over 12 months sit behind that.
Common questions
BOS to CHS questions
How often is BOS to CHS 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 23.5% of the 1,149 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 BOS to CHS?
Delta Air Lines leads at 76.2% on time across 370 flights. JetBlue Airways is at the other end on 75.3%, a gap of about a point. 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 BOS to CHS?
The 5am–8am departure window is the strongest at 84.0% on time. The 5pm–8pm window is the weakest at 60.5%, 24 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 BOS to CHS?
December is the weakest month at 61.6% on time, compared with 85.5% in May. 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
- CHS to BOS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- Charleston International (CHS) delay statistics
- Republic Airways on BOS to CHS85.0%
- Delta Air Lines on BOS to CHS76.2%
- JetBlue Airways on BOS to CHS75.3%
- BOS to DCA, a related route72.6%
- ATL to CHS, a related route82.3%
- BOS to ORD, a related route71.9%
- Republic Airways on-time record85.0%
- Delta Air Lines on-time record76.2%
- JetBlue Airways on-time record75.3%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. BOS to CHS and CHS to BOS 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.