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DelayAtlas

Chicago, IL · departure reliability

ORD

Chicago O'Hare International

Departures
355,671
Period
June 2025 to May 2026
Carriers
12
US rank
#1 by volume
CGRADE
Terminal building and aircraft stands at a US airport

Chicago

Chicago O'Hare International 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 355,671 flights, of which JetBlue Airways flew 1,086 at 77.7% on time.

JetBlue Airways is the most reliable of the twelve carriers covered here at 77.7% on time across 1,086 flights.

Key figures

On time

70.8%

Departures arriving under 15 minutes late at their destination

Avg delay

78 min

Across delayed flights only

Cancelled

2.48%

National rate is 1.80%

Best carrier

JetBlue

77.7% on time here

These figures cover 356,000 flights between June 2025 and May 2026. Beyond the headline rate, 11.8% 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 airlines run best out of ORD

The choice of carrier is not cosmetic here. JetBlue Airways arrives on time 77.7% of the time; PSA Airlines manages 59.2%. Sample sizes sit next to every figure, because a two-point gap across 3,619 flights means less than a ten-point one.

On-time performance by carrier departing ORD
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines98,67573.2%70 min1.14%C
SkyWest Airlines75,60065.4%88 min3.54%C−
American Airlines60,47767.1%82 min2.56%C
Envoy Air56,95375.6%61 min2.53%B
Republic Airways31,83575.9%72 min3.28%B−
Delta Air Lines10,53372.6%91 min2.39%C
Spirit Airlines5,12767.0%84 min4.45%C−
Southwest Airlines4,36269.6%67 min1.22%C
Frontier Airlines4,19466.3%104 min3.43%C−
PSA Airlines3,61959.2%131 min6.60%D−
Alaska Airlines3,21068.9%62 min1.56%C
JetBlue Airways1,08677.7%94 min3.22%B−

PSA Airlines cancels 6.6% 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.

Route by route

Busiest routes out of ORD

Route-level records vary far more than the airport average. These are the 25 busiest departures from ORD, each with its own on-time rate against the airport-wide 70.8%.

Busiest routes from ORD by flight volume
RouteFlightsOn timeAvg delayCancelledGrade
ORD to LGA · New York11,63467.0%85 min4.51%C−
ORD to BOS · Boston7,56167.7%78 min2.59%C
ORD to LAX · Los Angeles6,98173.6%73 min1.52%C
ORD to DFW · Dallas-Fort Worth6,92569.8%87 min2.93%C
ORD to DCA · Washington6,91868.5%82 min2.99%C
ORD to MCO · Orlando6,41972.5%74 min1.53%C
ORD to ATL · Atlanta6,39174.0%80 min2.17%C
ORD to MSP · Minneapolis6,33069.4%80 min2.02%C
ORD to DEN · Denver6,19874.1%77 min1.16%C
ORD to IAH · Houston6,05974.7%74 min1.40%C
ORD to EWR · Newark5,99269.3%85 min3.15%C−
ORD to DTW · Detroit5,96170.7%83 min2.70%C
ORD to PHX · Phoenix5,63273.6%74 min1.63%C
ORD to SFO · San Francisco5,60770.2%72 min1.32%C
ORD to SEA · Seattle5,56168.6%65 min1.31%C
ORD to LAS · Las Vegas5,36774.1%71 min1.19%C
ORD to IND · Indianapolis5,19073.7%74 min3.28%C−
ORD to MKE · Milwaukee5,16763.7%91 min4.53%D−
ORD to BNA · Nashville5,03168.7%79 min2.37%C
ORD to CLE · Cleveland4,94369.8%77 min2.85%C
ORD to PHL · Philadelphia4,81870.6%93 min2.76%C
ORD to CMH · Columbus4,79472.0%74 min2.32%C
ORD to CVG · Cincinnati4,60771.4%72 min2.82%C
ORD to MIA · Miami4,45474.7%68 min1.86%C
ORD to CLT · Charlotte4,22872.9%82 min2.22%C

Departure window

The best time of day to leave ORD

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against 19 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am38,457 flights85.1%
  • 8am–11am77,169 flights77.1%
  • 11am–2pm57,623 flights74.2%
  • 2pm–5pm67,834 flights67.1%
  • 5pm–8pm62,499 flights61.3%
  • 8pm–5am52,089 flights62.6%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 61.3% on time, against 85.1% 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 ORD runs late

ORD's year swings by 18 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 month67J74F66M70A76M69J64J74A79S75O73N61D
Darker means more delays. Figures are on-time percentages.September best, December worst

December is the weak month at 61.0% on time, against 79.2% in September. 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.

Across the week, Tuesday is the strongest day at 75.1% on time and Sunday the weakest at 66.9%. 8 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week68.5Mon75.1Tue72.2Wed72.1Thu68.7Fri72.4Sat66.9Sun
Monday: 68.5 percent on time. Tuesday: 75.1 percent on time. Wednesday: 72.2 percent on time. Thursday: 72.1 percent on time. Friday: 68.7 percent on time. Saturday: 72.4 percent on time. Sunday: 66.9 percent on time

Delay causes

Why ORD 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 7.87 million reported delay minutes.

  • Late-arriving aircraft
    41%
  • Carrier
    29%
  • National Airspace System
    20%
  • Extreme weather
    10%
  • Security
    0%

41% 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 7.87 million reported delay minutes here, that single category outweighs weather by 4 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 85.1% on time here.

Cancellations sit at 2.48% against a national 1.80%, which is ordinary. Diversions add another 0.29%.

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.8% 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.

355,671 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

What to do with this

Flying out of ORD

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 79.2% on time and December 61.0%, a swing of 18 points. If the dates move at all, move them out of December before you think about anything else.

Common questions

ORD delay questions

How often is Chicago (ORD) 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 29.2% of the 355,671 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 Chicago (ORD)?

JetBlue Airways leads at 77.7% on time across 1,086 flights. PSA Airlines is at the other end on 59.2%, a gap of 19 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 Chicago (ORD)?

The 5am–8am departure window is the strongest at 85.1% on time. The 5pm–8pm window is the weakest at 61.3%, 24 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 Chicago (ORD)?

December is the weakest month at 61.0% on time, compared with 79.2% in September. Across the year that is 18 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

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