Route reliability record

BWI→MIA

Baltimore to Miami

Flights: 2,286
Period: July 2025 to June 2026
Distance: 946 mi
Carriers: 5

This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,286 flights, of which American Airlines flew 689 at 80.4% on time.

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.

On time

74.7%

Arrivals under 15 minutes late, of 2,231 completed flights

Avg delay

73 min

Across delayed arrivals only, not all flights

Cancelled

2.10%

National rate is 1.81%

Best carrier

American

80.4% on time across 689 flights

These figures cover 2,286 flights between July 2025 and June 2026. Beyond the headline rate, 8.9% 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 BWI to MIA

The choice of carrier is not cosmetic here. American Airlines arrives on time 80.4% of the time; Southwest Airlines manages 72.3%. Sample sizes sit next to every figure, because a two-point gap across 1,181 flights means less than a ten-point one.

On-time performance by carrier on BWI to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	114	81.6%	62 min	0.00%	B+
American Airlines	689	80.4%	101 min	2.32%	B
Southwest Airlines	1,181	72.3%	59 min	1.86%	C
Frontier Airlinesthin sample	265	69.4%	89 min	3.40%	C−
Spirit Airlinesthin sample	37	61.1%	64 min	2.70%	D

American leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh 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 30 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am435 flights89.0%
8am–11am452 flights81.6%
11am–2pm383 flights78.1%
2pm–5pm187 flights61.7%
5pm–8pm640 flights66.3%
8pm–5am189 flights59.2%

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

The 8pm–5am window is where this operation falls apart: 59.2% on time, against 89.0% 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 5pm–8pm window is the busiest, with 640 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.

Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 59.4% on time, 31 points below September, the best at 90.2%. 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. December was the busiest month here, with 218 flights.

Across the week, Tuesday is the strongest day at 79.9% on time and Sunday the weakest at 66.4%. 14 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 41,000 reported delay minutes.

Late-arriving aircraft
39%
Carrier
29%
National Airspace System
24%
Extreme weather
7%
Security
0%

39% 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 41,000 reported delay minutes here, that single category outweighs weather by 6 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 41,183 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 89.0% on time here.

Cancellations sit at 2.10% against a national 1.81%, which is ordinary. Diversions add another 0.31%.

Connections and stage length

What a delay here actually costs

8.9% 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 are the a little over an hour kind, which a normal layover absorbs.

The 946 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 73.6% on time across 2,284 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 2,286 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 calendar is the biggest lever here, not the carrier or the hour. September runs 90.2% on time and July 59.4%, a swing of 31 points. If the dates move at all, move them out of July before you think about anything else. 2,231 completed flights over 12 months sit behind that.

Common questions

BWI to MIA questions

How often is BWI to MIA delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.3% of the 2,286 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 BWI to MIA?

American Airlines leads at 80.4% on time across 689 flights. Southwest Airlines is at the other end on 72.3%, a gap of 8 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 BWI to MIA?

The 5am–8am departure window is the strongest at 89.0% on time. The 8pm–5am window is the weakest at 59.2%, 30 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 BWI to MIA?

July is the weakest month at 59.4% on time, compared with 90.2% in September. 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.

Where to go next

Direction matters. BWI to MIA and MIA to BWI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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

Key figures