Route reliability record

STL→LGA

St. Louis to New York

Flights: 2,645
Period: July 2025 to June 2026
Distance: 888 mi
Carriers: 3

This route carries a cancellation problem, not just a delay problem: 3.8% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four 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 2,645 flights, of which Republic Airways flew 1,227 at 80.3% 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

74.9%

Arrivals under 15 minutes late, of 2,529 completed flights

Avg delay

67 min

Across delayed arrivals only, not all flights

Cancelled

3.78%

National rate is 1.81%

Best carrier

Republic

80.3% on time across 1,227 flights

These figures cover 2,645 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 STL to LGA

The choice of carrier is not cosmetic here. Republic Airways arrives on time 80.3% of the time; Southwest Airlines manages 70.4%. Sample sizes sit next to every figure, because a two-point gap across 1,390 flights means less than a ten-point one.

On-time performance by carrier on STL to LGA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airways	1,227	80.3%	85 min	4.56%	B−
Southwest Airlines	1,390	70.4%	57 min	3.17%	C−
SkyWest Airlinesthin sample	28	66.7%	78 min	0.00%	C+

Republic Airways cancels 4.6% 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 32 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am732 flights89.5%
8am–11am278 flights85.1%
11am–2pm593 flights71.0%
2pm–5pm520 flights69.0%
5pm–8pm303 flights59.3%
8pm–5am219 flights57.7%

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

The 8pm–5am window is where this operation falls apart: 57.7% on time, against 89.5% 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 5am–8am window is the busiest, with 732 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 23 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.January best, March worst

Delays peak in March, when the on-time rate falls to 63.5%. January is the strongest month at 86.2%. Moving a flexible trip across that boundary buys 23 points. March was the busiest month here, with 254 flights.

Across the week, Wednesday is the strongest day at 81.6% on time and Sunday the weakest at 66.7%. 15 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 43,000 reported delay minutes.

Late-arriving aircraft
35%
National Airspace System
35%
Carrier
26%
Extreme weather
4%
Security
0%

35% 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 43,000 reported delay minutes here, that single category outweighs weather by 9 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 42,774 reported delay minutes.

35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 15,000 minutes out of 43,000, against a national NAS share of 21%.

Cancellations run at 3.78%, 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. 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 888 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 75.6% on time across 2,644 flights, within half 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 2,645 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 3.78% cancellation rate. A late arrival costs you about an hour; 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. 2,529 completed flights over 12 months sit behind that.

Common questions

STL to LGA questions

How often is STL to LGA 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 25.1% of the 2,645 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 LGA?

Republic Airways leads at 80.3% on time across 1,227 flights. Southwest Airlines is at the other end on 70.4%, a gap of 10 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 LGA?

The 5am–8am departure window is the strongest at 89.5% on time. The 8pm–5am window is the weakest at 57.7%, 32 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 March delays on STL to LGA?

March is the weakest month at 63.5% on time, compared with 86.2% in January. Across the year that is 23 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 LGA and LGA 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