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DelayAtlas

Route reliability record

LGAMIA

New York to Miami

Flights
6,006
Period
July 2025 to June 2026
Distance
1,096 mi
Carriers
5
C−GRADE

This route carries a cancellation problem, not just a delay problem: 4.1% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, about seven flights in ten arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 6,006 flights, of which American Airlines flew 3,549 at 71.5% on time.

American Airlines is the most reliable of the three carriers covered here at 71.5% on time across 3,549 flights.

Key figures

On time

70.6%

Arrivals under 15 minutes late, of 5,734 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

4.13%

National rate is 1.81%

Best carrier

American

71.5% on time across 3,549 flights

These figures cover 6,006 flights between July 2025 and June 2026. Beyond the headline rate, 12.6% 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 LGA to MIA

The three carriers here are closely matched: 5 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 LGA to MIA
AirlineFlightsOn timeAvg delayCancelledGrade
Republic Airwaysthin sample475.0%107 min0.00%B+
American Airlines3,54971.5%93 min3.69%C−
Delta Air Lines1,91670.2%69 min3.97%C−
Frontier Airlinesthin sample11967.3%247 min10.08%C−
Spirit Airlines41866.1%79 min6.94%C−

Spirit Airlines cancels 6.9% 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.

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 31 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am1,136 flights89.3%
  • 8am–11am742 flights78.1%
  • 11am–2pm1,301 flights69.6%
  • 2pm–5pm795 flights61.8%
  • 5pm–8pm1,374 flights58.4%
  • 8pm–5am658 flights68.2%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 58.4% on time, against 89.3% 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 5pm–8pm window is the busiest, with 1,374 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 month75J77F64M75A75M77J65J71A75S67O65N62D
Darker means more delays. Figures are on-time percentages.February best, December worst

December is the weak month at 62.0% on time, against 77.2% in February. 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 575 flights.

Across the week, Saturday is the strongest day at 75.3% on time and Sunday the weakest at 58.8%. 17 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week68.7Mon74.9Tue74.8Wed69.1Thu72.9Fri75.3Sat58.8Sun
Monday: 68.7 percent on time. Tuesday: 74.9 percent on time. Wednesday: 74.8 percent on time. Thursday: 69.1 percent on time. Friday: 72.9 percent on time. Saturday: 75.3 percent on time. Sunday: 58.8 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 147,000 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.

  • Late-arriving aircraft
    48%
  • National Airspace System
    26%
  • Carrier
    21%
  • Extreme weather
    5%
  • Security
    0%

48% 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 147,000 reported delay minutes here, that single category outweighs weather by 10 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 146,831 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 89.3% on time here.

Cancellations run at 4.13%, against 1.81% nationally. That is about one flight in 25 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. 12.6% 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 1,096 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 68.0% on time across 6,010 flights, within 3 points 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 6,006 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.

What to do with this

Booking this route

Put together: the delay figures matter less here than the 4.13% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 5,734 completed flights over 12 months sit behind that.

Common questions

LGA to MIA questions

How often is LGA to MIA delayed?

Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.4% of the 6,006 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 LGA to MIA?

American Airlines leads at 71.5% on time across 3,549 flights. Spirit Airlines is at the other end on 66.1%, a gap of 5 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 LGA to MIA?

The 5am–8am departure window is the strongest at 89.3% on time. The 5pm–8pm window is the weakest at 58.4%, 31 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 LGA to MIA?

December is the weakest month at 62.0% on time, compared with 77.2% in February. 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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.