Route reliability record
JAX→MIA
Jacksonville to Miami
- Flights
- 1,525
- Period
- July 2025 to June 2026
- Distance
- 335 mi
- Carriers
- 3
This route lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,525 JAX to MIA flights, of which Envoy Air flew 702 at 80.7% on time.
Best time to fly JAX to MIA: a 11am–2pm departure, ideally on a Monday. Flights in that window arrived on time 90.9% of the time and Monday flights 83.6%, against 80.5% 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
80.5%
Arrivals under 15 minutes late, of 1,509 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
0.92%
National rate is 1.81%
Best carrier
Envoy
80.7% on time across 702 flights
These figures cover 1,525 flights between July 2025 and June 2026. The median arrival is 6 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 JAX to MIA
The two carriers here are closely matched: half 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 |
|---|---|---|---|---|---|
| Envoy Air | 702 | 80.7% | 52 min | 0.85% | B+ |
| American Airlines | 803 | 80.2% | 92 min | 1.00% | B |
| Republic Airwaysthin sample | 20 | 80.0% | 113 min | 0.00% | B+ |
No carrier stands out. Envoy tops the table at 80.7%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Best ways to make this trip
The most reliable ways to fly Jacksonville to Miami
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. JAX → MIAJacksonville to Miami | Envoy Air | 80.0% | 80.7% | 0.85% | 5am–8am, Mon | — |
| 2. JAX → MIAJacksonville to Miami | American Airlines | 79.4% | 80.2% | 1.00% | 11am–2pm, Thu | — |
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 27 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–8am547 flights90.6%
- 8am–11am376 flights83.5%
- 11am–2pm44 flights90.9%
- 2pm–5pm85 flights66.7%
- 5pm–8pm397 flights68.3%
- 8pm–5am76 flights63.5%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 63.5% on time, against 90.9% for the 11am–2pm 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 5am–8am window is the busiest, with 547 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 16 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.
July is the worst month at 73.2% on time, 16 points below November, the best at 88.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 157 flights.
Across the week, Monday is the strongest day at 83.6% on time and Sunday the weakest at 72.4%. 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. Carrier accounts for 44% of the 22,000 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.
- 44%Carrier
- 40%Late-arriving aircraft
- 13%National Airspace System
- 4%Extreme weather
40% 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 22,000 reported delay minutes here, that single category outweighs weather by 11 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 21,918 reported delay minutes.
The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 9,554 of the 22,000 delay minutes reported here.
Cancellations sit at 0.92% against a national 1.81%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here actually costs
7.4% 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 a little over an hour, which a normal layover absorbs.
At 335 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 11am–2pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 74.1% on time across 1,526 flights, 6 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 6 points of difference.
The sample behind these figures is 1,525 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 MIA 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. November runs 88.7% on time and July 73.2%, a swing of 16 points. If the dates move at all, move them out of July before you think about anything else. 1,509 completed flights over 12 months sit behind that.
Common questions
JAX to MIA questions
How often is JAX to MIA delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.5% of the 1,525 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on JAX to MIA?
Envoy Air leads at 80.7% on time across 702 flights. American Airlines is at the other end on 80.2%, a gap of half 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 JAX to MIA?
The 11am–2pm departure window is the strongest at 90.9% on time. The 8pm–5am window is the weakest at 63.5%, 27 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 July delays on JAX to MIA?
July is the weakest month at 73.2% on time, compared with 88.7% in November. Across the year that is 16 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
- MIA to JAX — the return legseparate record
- Miami International (MIA) delay statistics
- Envoy Air on JAX to MIA80.7%
- American Airlines on JAX to MIA80.2%
- JAX to ATL, a related route84.9%
- ATL to MIA, a related route71.0%
- JAX to ORD, a related route77.3%
- Envoy Air on-time record80.7%
- American Airlines on-time record80.2%
- Republic Airways on-time record80.0%
- 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. JAX to MIA and MIA to JAX 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.