Route reliability record

STL→MCO

St. Louis to Orlando

Flights: 2,497
Period: July 2025 to June 2026
Distance: 882 mi
Carriers: 3

This route lands a B+, level with the national rate of 77.6%. Roughly one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 2,497 flights, of which Southwest Airlines flew 2,092 at 79.0% 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

78.0%

Arrivals under 15 minutes late, of 2,459 completed flights

Avg delay

62 min

Across delayed arrivals only, not all flights

Cancelled

0.96%

National rate is 1.81%

Best carrier

Southwest

79.0% on time across 2,092 flights

These figures cover 2,497 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 STL to MCO

The choice of carrier is not cosmetic here. Southwest Airlines arrives on time 79.0% of the time; Frontier Airlines manages 72.6%. Sample sizes sit next to every figure, because a two-point gap across 395 flights means less than a ten-point one.

On-time performance by carrier on STL to MCO
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	10	90.0%	25 min	0.00%	A+
Southwest Airlines	2,092	79.0%	59 min	0.62%	B+
Frontier Airlines	395	72.6%	77 min	2.78%	C

Southwest leads Frontier by 6 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 28 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am516 flights93.2%
8am–11am434 flights84.9%
11am–2pm261 flights79.5%
2pm–5pm563 flights69.5%
5pm–8pm589 flights69.9%
8pm–5am134 flights65.2%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.2% of the time, against 65.2% for the overnight window. That is 28 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 589 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.

Darker means more delays. Figures are on-time percentages.April best, December worst

December is the weak month at 70.0% on time, against 85.9% in April. 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 269 flights.

Across the week, Wednesday is the strongest day at 86.7% on time and Saturday the weakest at 70.1%. 17 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. Late-arriving aircraft accounts for 50% of the 34,000 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
50%
Carrier
25%
National Airspace System
22%
Extreme weather
2%
Security
0%

50% 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 34,000 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 33,720 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 93.2% on time here.

Cancellations sit at 0.96% against a national 1.81%, which is ordinary. Diversions add another 0.56%.

Connections and stage length

What a delay here actually costs

7.3% 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 about an hour kind, which a normal layover absorbs.

The 882 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 77.0% on time across 2,485 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 2,497 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. April runs 85.9% on time and December 70.0%, a swing of 16 points. If the dates move at all, move them out of December before you think about anything else. 2,459 completed flights over 12 months sit behind that.

Common questions

STL to MCO questions

How often is STL to MCO delayed?

Roughly one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.0% of the 2,497 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on STL to MCO?

Southwest Airlines leads at 79.0% on time across 2,092 flights. Frontier Airlines is at the other end on 72.6%, a gap of 6 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 STL to MCO?

The 5am–8am departure window is the strongest at 93.2% on time. The 8pm–5am window is the weakest at 65.2%, 28 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 STL to MCO?

December is the weakest month at 70.0% on time, compared with 85.9% in April. 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.

Where to go next

Direction matters. STL to MCO and MCO to STL 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