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DelayAtlas

Route reliability record

BOSJAX

Boston to Jacksonville

Flights
1,606
Period
July 2025 to June 2026
Distance
1,011 mi
Carriers
3
BGRADE

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, 2 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,606 BOS to JAX flights, of which JetBlue Airways flew 658 at 75.9% on time.

Best time to fly BOS to JAX: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 86.9% of the time and Saturday flights 79.9%, against 75.4% for the route overall.

The US average over the same twelve months is 77.6%, 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

75.4%

Arrivals under 15 minutes late, of 1,563 completed flights

Avg delay

65 min

Across delayed arrivals only, not all flights

Cancelled

2.55%

National rate is 1.81%

Best carrier

JetBlue

75.9% on time across 658 flights

These figures cover 1,606 flights between July 2025 and June 2026. Beyond the headline rate, 9.5% 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 BOS to JAX

The two carriers here are closely matched: 2 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.

On-time performance by carrier on BOS to JAX
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Linesthin sample5684.9%80 min5.36%B−
JetBlue Airways65875.9%71 min2.74%B
Republic Airways89274.4%61 min2.24%C

No carrier stands out. JetBlue tops the table at 75.9%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Flight by flight

Flights on BOS to JAX

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 Boston to Jacksonville

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.

Most reliable ways to fly from BOS to JAX
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. BOSJAXBoston to JacksonvilleJetBlue Airways73.8%75.9%2.74%5am–8am, TueB6 109 06:20
2. BOSJAXBoston to JacksonvilleRepublic Airways72.7%74.4%2.24%8am–11am, Wed

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.

Plan this trip by month, day and time

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 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am268 flights86.9%
  • 8am–11am453 flights83.8%
  • 11am–2pm26 flights
  • 2pm–5pm487 flights69.1%
  • 5pm–8pm249 flights64.6%
  • 8pm–5am123 flights68.9%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 64.6% on time, against 86.9% 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 487 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 15 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.

On-time rate by calendar month69J71F74M80A83M82J68J81A77S72O75N67D
Darker means more delays. Figures are on-time percentages.May best, December worst

December is the weak month at 67.4% on time, against 82.5% 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 160 flights.

Across the week, Saturday is the strongest day at 79.9% on time and Sunday the weakest at 69.5%. 10 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week75.7Mon79.8Tue79.5Wed70.6Thu73.9Fri79.9Sat69.5Sun
Monday: 75.7 percent on time. Tuesday: 79.8 percent on time. Wednesday: 79.5 percent on time. Thursday: 70.6 percent on time. Friday: 73.9 percent on time. Saturday: 79.9 percent on time. Sunday: 69.5 percent on time

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 25,000 reported delay minutes.

  • Late-arriving aircraft
    41%
  • Carrier
    31%
  • National Airspace System
    26%
  • Extreme weather
    2%
  • Security
    0%

41% 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 25,000 reported delay minutes here, that single category outweighs weather by 21 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 25,178 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 86.9% on time here.

Cancellations run at 2.55%, against 1.81% 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.5% 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 1,011 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 runs 74.4% on time across 1,609 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 1,606 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 JAX 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 82.5% on time and December 67.4%, a swing of 15 points. If the dates move at all, move them out of December before you think about anything else. 1,563 completed flights over 12 months sit behind that.

Common questions

BOS to JAX questions

How often is BOS to JAX 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 24.6% of the 1,606 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on BOS to JAX?

JetBlue Airways leads at 75.9% on time across 658 flights. Republic Airways is at the other end on 74.4%, a gap of 2 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 BOS to JAX?

The 5am–8am departure window is the strongest at 86.9% on time. The 5pm–8pm window is the weakest at 64.6%, 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 BOS to JAX?

December is the weakest month at 67.4% on time, compared with 82.5% in May. Across the year that is 15 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

Direction matters. BOS to JAX and JAX 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.