Route reliability record

LGA→DEN

New York to Denver

Flights: 4,672
Period: June 2025 to May 2026
Distance: 1,620 mi
Carriers: 4

This route sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.4%. The late ones land a little over an hour behind schedule. That rests on 4,672 flights, of which United Airlines flew 2,012 at 77.5% on time.

United Airlines is the most reliable of the three carriers covered here at 77.5% on time across 2,012 flights.

On time

70.9%

Arrivals under 15 minutes late, of 4,501 completed flights

Avg delay

71 min

Across delayed arrivals only, not all flights

Cancelled

3.04%

National rate is 1.80%

Best carrier

United

77.5% on time across 2,012 flights

These figures cover 4,672 flights between June 2025 and May 2026. Beyond the headline rate, 10.8% 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 DEN

The choice of carrier is not cosmetic here. United Airlines arrives on time 77.5% of the time; Southwest Airlines manages 61.9%. Sample sizes sit next to every figure, because a two-point gap across 1,441 flights means less than a ten-point one.

On-time performance by carrier on LGA to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	2,012	77.5%	72 min	1.99%	B
Delta Air Lines	1,038	71.6%	78 min	4.34%	C−
Frontier Airlinesthin sample	181	62.8%	93 min	4.97%	D−
Southwest Airlines	1,441	61.9%	64 min	3.33%	D−

Delta Air Lines cancels 4.3% 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 33 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am1,019 flights88.0%
8am–11am472 flights80.9%
11am–2pm587 flights79.4%
2pm–5pm1,085 flights64.8%
5pm–8pm1,138 flights57.1%
8pm–5am371 flights55.2%

Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 55.2% on time, against 88.0% 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.

Across the year

When delays peak on this route

This route's year swings by 22 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, July worst

July is the worst month at 61.0% on time, 22 points below January, the best at 82.6%. 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.

Across the week, Saturday is the strongest day at 79.0% on time and Sunday the weakest at 66.6%. 12 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 93,000 reported delay minutes.

Late-arriving aircraft
40%
Carrier
27%
National Airspace System
27%
Extreme weather
5%
Security
0%

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 93,000 reported delay minutes here, that single category outweighs weather by 7 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 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 88.0% on time here.

Cancellations run at 3.04%, against 1.80% nationally. That is roughly one flight in 30 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. 10.8% of arrivals land a full hour or more behind schedule, against 8.2% 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.

At 1,620 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 71.5% on time across 4,673 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 4,672 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 3.04% cancellation rate. A late arrival costs you a little over 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.

Common questions

LGA to DEN questions

How often is LGA to DEN 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 29.1% of the 4,672 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on LGA to DEN?

United Airlines leads at 77.5% on time across 2,012 flights. Southwest Airlines is at the other end on 61.9%, a gap of 16 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 DEN?

The 5am–8am departure window is the strongest at 88.0% on time. The 8pm–5am window is the weakest at 55.2%, 33 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 LGA to DEN?

July is the weakest month at 61.0% on time, compared with 82.6% in January. Across the year that is 22 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. LGA to DEN and DEN to LGA 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, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures