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DelayAtlas

Route reliability record

JFKDEN

New York to Denver

Flights
1,572
Period
July 2025 to June 2026
Distance
1,626 mi
Carriers
3
CGRADE

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, 6 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,572 JFK to DEN flights, of which Delta Air Lines flew 978 at 73.2% on time.

Best time to fly JFK to DEN: a 11am–2pm departure, ideally on a Tuesday. Flights in that window arrived on time 84.2% of the time and Tuesday flights 83.8%, against 71.4% for the route overall.

The national on-time rate over the same period is 77.6%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 62 extra late arrivals.

Key figures

On time

71.4%

Arrivals under 15 minutes late, of 1,529 completed flights

Avg delay

67 min

Across delayed arrivals only, not all flights

Cancelled

2.54%

National rate is 1.81%

Best carrier

Delta

73.2% on time across 978 flights

These figures cover 1,572 flights between July 2025 and June 2026. Beyond the headline rate, 10.5% 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 JFK to DEN

The two 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 JFK to DEN
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines97873.2%71 min2.56%C
JetBlue Airways54568.7%55 min2.75%C
Frontier Airlinesthin sample4967.3%124 min0.00%C+

No carrier stands out. Delta tops the table at 73.2%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Flight by flight

Flights on JFK to DEN

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

Best ways to make this trip

The most reliable ways to fly New York to Denver

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.

Most reliable ways to fly from JFK to DEN
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. EWRDENNewark to DenverUnited Airlines77.3%78.3%1.31%5am–8am, MonUA 2120 14:10
2. LGADENNew York to DenverUnited Airlines76.3%77.8%1.98%5am–8am, TueUA 2200 12:30
3. JFKDENNew York to DenverDelta Air Lines71.3%73.2%2.56%8am–11am, TueDL 424 19:55
4. LGADENNew York to DenverDelta Air Lines68.3%71.3%4.15%5am–8am, SatDL 751 07:30
5. JFKDENNew York to DenverJetBlue Airways66.8%68.7%2.75%8am–11am, TueB6 97 20:18

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

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

  • 5am–8am25 flights
  • 8am–11am610 flights81.7%
  • 11am–2pm38 flights84.2%
  • 2pm–5pm231 flights60.8%
  • 5pm–8pm170 flights63.5%
  • 8pm–5am498 flights65.9%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 84.2% on time, ahead of 2pm–5pm at 60.8%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8am–11am window is the busiest, with 610 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 33 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 month79J79F65M75A79M74J55J74A88S69O69N60D
Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 55.3% on time, 33 points below September, the best at 88.1%. 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 157 flights.

Across the week, Tuesday is the strongest day at 83.8% on time and Sunday the weakest at 64.3%. 20 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week70.8Mon83.8Tue76.6Wed68.8Thu69.3Fri66.3Sat64.3Sun
Monday: 70.8 percent on time. Tuesday: 83.8 percent on time. Wednesday: 76.6 percent on time. Thursday: 68.8 percent on time. Friday: 69.3 percent on time. Saturday: 66.3 percent on time. Sunday: 64.3 percent on time

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 29,000 reported delay minutes.

  • National Airspace System
    38%
  • Carrier
    35%
  • Late-arriving aircraft
    25%
  • Extreme weather
    2%
  • Security
    0%

38% 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 11,000 minutes out of 29,000, against a national NAS share of 21%. The split is drawn from 29,246 reported delay minutes.

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 10,000 of the 29,000 delay minutes reported here.

Cancellations run at 2.54%, against 1.81% nationally. That is about one flight in 40 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. 10.5% 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.

At 1,626 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 is a different operation and performs like one: it runs 81.0% on time across 1,572 flights, 10 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.

The sample behind these figures is 1,572 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.

Work out the risk of missing a connection in DEN after this flight

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 88.1% on time and July 55.3%, a swing of 33 points. If the dates move at all, move them out of July before you think about anything else. 1,529 completed flights over 12 months sit behind that.

Common questions

JFK to DEN questions

How often is JFK to DEN delayed?

Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.6% of the 1,572 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on JFK to DEN?

Delta Air Lines leads at 73.2% on time across 978 flights. JetBlue Airways is at the other end on 68.7%, 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 JFK to DEN?

The 11am–2pm departure window is the strongest at 84.2% on time. The 2pm–5pm window is the weakest at 60.8%, 23 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 JFK to DEN?

July is the weakest month at 55.3% on time, compared with 88.1% in September. Across the year that is 33 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

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

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Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.