Route reliability record
CHS→BOS
Charleston to Boston
- Flights
- 1,131
- Period
- July 2025 to June 2026
- Distance
- 818 mi
- Carriers
- 3
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,131 CHS to BOS flights, of which JetBlue Airways flew 651 at 71.2% on time.
Best time to fly CHS to BOS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 91.5% of the time and Saturday flights 80.0%, against 71.3% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 63 extra late arrivals.
Key figures
On time
71.3%
Arrivals under 15 minutes late, of 1,107 completed flights
Avg delay
82 min
Across delayed arrivals only, not all flights
Cancelled
2.12%
National rate is 1.81%
Best carrier
JetBlue
71.2% on time across 651 flights
These figures cover 1,131 flights between July 2025 and June 2026. Beyond the headline rate, 13.0% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on CHS to BOS
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 |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 90 | 84.3% | 90 min | 1.11% | B |
| JetBlue Airways | 651 | 71.2% | 77 min | 1.84% | C |
| Delta Air Lines | 390 | 68.3% | 90 min | 2.82% | C |
No carrier stands out. JetBlue tops the table at 71.2%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on CHS to BOS
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.
Best ways to make this trip
The most reliable ways to fly Charleston to Boston
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. CHS → BOSCharleston to Boston | JetBlue Airways | 69.9% | 71.2% | 1.84% | 5am–8am, Sat | B6 68 13:19 |
| 2. CHS → BOSCharleston to Boston | Delta Air Lines | 66.4% | 68.3% | 2.82% | 11am–2pm, Sat | DL 2785 16:00 |
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 33 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am59 flights91.5%
- 8am–11am139 flights89.8%
- 11am–2pm340 flights69.1%
- 2pm–5pm413 flights67.4%
- 5pm–8pm94 flights66.7%
- 8pm–5am86 flights59.0%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.0% on time, against 91.5% 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 2pm–5pm window is the busiest, with 413 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 31 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 September, when the on-time rate falls to 50.5%. March is the strongest month at 81.2%. Moving a flexible trip across that boundary buys 31 points. May was the busiest month here, with 125 flights.
Across the week, Saturday is the strongest day at 80.0% on time and Thursday the weakest at 65.1%. 15 points is a smaller lever than departure hour, but it is free.
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 26,000 reported delay minutes.
- 36%Late-arriving aircraft
- 35%National Airspace System
- 28%Carrier
- 1%Extreme weather
36% 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 26,000 reported delay minutes here, that single category outweighs weather by 25 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 26,114 reported delay minutes.
35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 9,046 minutes out of 26,000, against a national NAS share of 21%.
Cancellations sit at 2.12% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 13.0% of arrivals land a full hour or more behind schedule, against 8.1% 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.
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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 77.2% on time across 1,130 flights, 6 points above 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 6 points of difference.
The sample behind these figures is 1,131 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 BOS 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. March runs 81.2% on time and September 50.5%, a swing of 31 points. If the dates move at all, move them out of September before you think about anything else. 1,107 completed flights over 12 months sit behind that.
Common questions
CHS to BOS questions
How often is CHS to BOS delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.7% of the 1,131 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on CHS to BOS?
JetBlue Airways leads at 71.2% on time across 651 flights. Delta Air Lines is at the other end on 68.3%, a gap of 3 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 CHS to BOS?
The 5am–8am departure window is the strongest at 91.5% on time. The 8pm–5am window is the weakest at 59.0%, 33 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 September delays on CHS to BOS?
September is the weakest month at 50.5% on time, compared with 81.2% in March. Across the year that is 31 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
- BOS to CHS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- JetBlue Airways on CHS to BOS71.2%
- Delta Air Lines on CHS to BOS68.3%
- CHS to ATL, a related route90.2%
- DCA to BOS, a related route71.4%
- CHS to CLT, a related route83.8%
- Republic Airways on-time record84.3%
- JetBlue Airways on-time record71.2%
- Delta Air Lines on-time record68.3%
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Direction matters. CHS to BOS and BOS 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.