Route profile
ORD→BOS
Flight reliability, delays and best times to fly from Chicago to Boston, 867 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 10% of comparable major US routes (4,598 compared)
Calculated from 21,895 flights. How this is calculated
ORD → BOS arrives on time 72.4% of the time; the return trip, BOS → ORD, arrives on time 76.9% of the time, a 4.6-point gap between the two directions of the same city pair.
ORD → BOS spends 32.3 minutes on the ground on an 867-mile trip: 24.8 minutes from pushback to wheels-up at ORD and 7.5 minutes from touchdown to gate at BOS.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route's worst arrivals run unusually far past its typical one, a bigger gap than 95% of 4,598 comparable routes.
A typical arrival is 5 min early, but the worst tenth run 76 minutes worse than that.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,598 in the comparison.
Why ORD → BOS flights are cancelled
July 2023 – July 2026
ORD → BOS cancelled 421 of 21,895 scheduled flights — about 1 in every 52. The reason filed most often was extreme weather, 61.0% of the cancellations coded on this route — about 1 in every 85 scheduled flights.
Share of cancellations
Of 421 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
257 cancellations, 61.0% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
88 cancellations, 20.9% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
76 cancellations, 18.1% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
421 coded cancellations were recorded on ORD → BOS; the section appears from 50.
When it goes wrong
July 2023 – July 2026
71 min late
against a median of 5 min early
ORD → BOS has an average that understates its risk: a typical arrival is 5 min early, but the worst tenth are 76 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 21,895 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at BOS after arriving from ORD.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 41% | Likely to miss |
| 45 min | 27% | High risk |
| 60 min | 20% | High risk |
| 90 min | 12% | Some risk |
| 120 min | 7.1% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.92% of the time and diverts 0.21% of the time, which a late arrival never shows up in.
Chance of missing is the share of 21,427 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 71 minutes late (90th-percentile gate arrival delay), over 21,895 operations.
Any other layover length: connection checker.
Best time to fly
ORD → BOS flights departing 5–9 AM arrived on time 87.2% of the time, against 58.8% for 3–6 PM departures, a gap of 28.4 percentage points.
By day and hour
On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (ORD).
Hour of departure matters more than day of the week: hourly averages sit a typical 11.1 points from the route-wide rate, weekday averages 3.4 points.
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
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On-time rate, % · stronger color, fewer on time
- 40–49
- 50–59
- 60–69
- 70–79
- 80–89
- 90–99
- Fewer than 120 flights, not scored
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · On time is arrival within 15 minutes of schedule. Cells round to whole percentages; the table shows one decimal.
No slot is named best or worst: too few reach 500 flights. Departures before 6 AM and after 10 PM (12 flights) are not drawn: no slot in those hours has enough flights to score.
View as tableHide table
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
|---|---|---|---|---|---|---|---|
| 6 AM–7 AM | 90.5% on time257 flights | 88.9% on time202 flights | 91.5% on time204 flights | 91.4% on time244 flights | 85.9% on time256 flights | 89.9% on time151 flights | 88.8% on time217 flights |
| 7 AM–8 AM | 84.6% on time364 flights | 90.1% on time353 flights | 91.3% on time346 flights | 86.3% on time368 flights | 84.2% on time366 flights | 87.7% on time363 flights | 87.0% on time375 flights |
| 8 AM–9 AM | 80.3% on time209 flights | 87.8% on time203 flights | 85.0% on time208 flights | 87.7% on time205 flights | 77.0% on time209 flights | 88.7% on time188 flights | 85.9% on time221 flights |
| 9 AM–10 AM | 82.8% on time272 flights | 87.1% on time267 flights | 85.6% on time264 flights | 81.9% on time271 flights | 75.7% on time252 flights | 85.8% on time142 flights | 84.2% on time222 flights |
| 10 AM–11 AM | 73.7% on time233 flights | 77.4% on time230 flights | 82.1% on time225 flights | 76.9% on time225 flights | 79.0% on time227 flights | 77.0% on time186 flights | 76.8% on time197 flights |
| 11 AM–12 PM | 67.9% on time170 flights | 71.7% on time170 flights | 73.2% on time184 flights | 68.2% on time176 flights | 58.6% on time176 flights | 83.4% on time199 flights | 65.7% on time182 flights |
| 12 PM–1 PM | 98 flights, too few to score | 97 flights, too few to score | 102 flights, too few to score | 98 flights, too few to score | 98 flights, too few to score | 84.9% on time121 flights | 100 flights, too few to score |
| 1 PM–2 PM | 64.7% on time319 flights | 69.3% on time300 flights | 71.5% on time301 flights | 61.3% on time318 flights | 62.6% on time322 flights | 74.0% on time223 flights | 65.3% on time302 flights |
| 2 PM–3 PM | 64.4% on time137 flights | 72.1% on time136 flights | 69.5% on time133 flights | 63.4% on time136 flights | 61.9% on time149 flights | 81.8% on time122 flights | 58.2% on time145 flights |
| 3 PM–4 PM | 60.0% on time179 flights | 56.7% on time174 flights | 54.9% on time165 flights | 43.7% on time176 flights | 56.0% on time164 flights | 61.9% on time141 flights | 52.3% on time180 flights |
| 4 PM–5 PM | 66.1% on time121 flights | 81 flights, too few to score | 81 flights, too few to score | 117 flights, too few to score | 59.5% on time123 flights | 78 flights, too few to score | 110 flights, too few to score |
| 5 PM–6 PM | 54.7% on time133 flights | 57.0% on time138 flights | 66.7% on time147 flights | 62.1% on time136 flights | 51.5% on time137 flights | 74.0% on time180 flights | 57.0% on time148 flights |
| 6 PM–7 PM | 67.7% on time288 flights | 71.1% on time268 flights | 63.2% on time276 flights | 59.7% on time286 flights | 69.0% on time292 flights | 77.0% on time209 flights | 65.6% on time288 flights |
| 7 PM–8 PM | 59.4% on time187 flights | 63.5% on time161 flights | 55.4% on time162 flights | 56.1% on time181 flights | 64.8% on time180 flights | 63.9% on time122 flights | 54.2% on time173 flights |
| 8 PM–9 PM | 59.5% on time221 flights | 67.7% on time201 flights | 55.7% on time204 flights | 53.3% on time217 flights | 50.2% on time222 flights | 63.9% on time163 flights | 55.0% on time234 flights |
| 9 PM–10 PM | 67.7% on time129 flights | 48 flights, too few to score | 56 flights, too few to score | 62.5% on time132 flights | 55.1% on time130 flights | 73 flights, too few to score | 74.8% on time135 flights |
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 89.5% on time from 1,531 flights
- 7 AM: 87.3% on time from 2,535 flights
- 8 AM: 84.5% on time from 1,443 flights
- 9 AM: 83.1% on time from 1,690 flights
- 10 AM: 77.6% on time from 1,523 flights
- 11 AM: 70.1% on time from 1,257 flights
- 12 PM: 71.2% on time from 714 flights
- 1 PM: 66.6% on time from 2,085 flights
- 2 PM: 67.0% on time from 958 flights
- 3 PM: 54.9% on time from 1,179 flights
- 4 PM: 61.9% on time from 711 flights
- 5 PM: 61.1% on time from 1,019 flights
- 6 PM: 67.2% on time from 1,907 flights
- 7 PM: 59.5% on time from 1,166 flights
- 8 PM: 57.5% on time from 1,462 flights
- 9 PM: 68.7% on time from 703 flights
- 10 PM to 11 PM: too few flights to score
Why ORD → BOS runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for ORD → BOS. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on ORD → BOS, at 41.1%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 87.2% of the time and 3–6 PM departures 58.8%.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of ORD to BOS: 5.5 times the normal rate at ORD and 3.9 times at BOS. Cancelled in bad weather against normal hours: ORD 6.5% against 1.2%, BOS 5.3% against 1.4%. Flights that did leave ORD in bad weather arrived on time 55.7% of the time, against 77.1% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | ORD | BOS |
|---|---|---|
| Cancelled in bad weather | 6.5% | 5.3% |
| Cancelled in normal hours | 1.2% | 1.4% |
| Arrived on time, bad weather | 55.7% | 65.1% |
| Arrived on time, normal hours | 77.1% | 79.7% |
| Departures in bad weather | 104,455 | 60,840 |
Of the carriers on this route, United Airlines (3.5% cancelled against 7.4% for the other carriers at ORD) cancelled the fewest departures from ORD in bad weather and Envoy Air (8.6% cancelled against 6.9% for the other carriers at ORD) the most. One more carrier flies this route but has too few bad-weather departures from ORD to compare.
This route’s airlines in bad weather at ORD
All departures from ORD| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| United Airlines | 31,269 | 3.5%below the others | 7.4% |
| Delta Air Lines | 3,353 | 3.5%below the others | 6.2% |
| American Airlines | 17,789 | 5.4%below the others | 6.7% |
| Republic Airways | 9,471 | 8.1%above the others | 6.5% |
| Envoy Air | 14,228 | 8.6%above the others | 6.9% |
These are airport figures, not route figures: every scheduled departure from ORD and BOS, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from ORD on every route.
Weather source and limits. In full: ORD (airlines), BOS, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 7,618 | 74.5% | 1.50% | -5 min | 11.0% |
| American Airlines | 5,434 | 64.9% | 1.95% | 1 min | 15.6% |
| Delta Air Lines | 2,911 | 72.2% | 2.06% | -7 min | 13.2% |
| Republic Airways | 2,408 | 76.6% | 3.16% | -7 min | 8.9% |
| JetBlue | 1,825 | 72.8% | 1.92% | -8 min | 13.5% |
| Envoy Air | 1,423 | 84.7% | 1.48% | -10 min | 4.9% |
United Airlines flew 35.2% of the 21,619 flights listed. Republic Airways cancelled 3.16% of its flights here against 1.48% for Envoy Air.
Envoy Air arrived on time 19.8 percentage points more often than American Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| B6312 JetBlue | 8:40 AM | 1,023 | 79.2% |
Weekly and seasonal patterns
By day of week
Saturday is historically the most reliable day and Friday the least, a gap of 10.8 percentage points.
By month
- Jan: 74.4%
- Feb: 78.7%
- Mar: 75.1%
- Apr: 76.7%
- May: 70.6%
- Jun: 69.1%
- Jul: 64.9%
- Aug: 70.7%
- Sep: 67.2%
- Oct: 73.1%
- Nov: 80.3%
- Dec: 75.1%
July is historically the weakest month and November the strongest, a spread of 15.4 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 60.3% from 554 flights
- August 2023: 71.4% from 585 flights
- September 2023: 65.8% from 552 flights
- October 2023: 81.0% from 526 flights
- November 2023: 85.0% from 470 flights
- December 2023: 82.6% from 462 flights
- January 2024: 68.9% from 466 flights
- February 2024: 85.3% from 438 flights
- March 2024: 83.1% from 509 flights
- April 2024: 78.6% from 536 flights
- May 2024: 67.6% from 623 flights
- June 2024: 69.8% from 654 flights
- July 2024: 67.5% from 670 flights
- August 2024: 67.1% from 703 flights
- September 2024: 80.0% from 624 flights
- October 2024: 83.5% from 631 flights
- November 2024: 84.1% from 580 flights
- December 2024: 78.0% from 503 flights
- January 2025: 84.6% from 486 flights
- February 2025: 80.0% from 467 flights
- March 2025: 76.7% from 570 flights
- April 2025: 82.8% from 543 flights
- May 2025: 66.5% from 645 flights
- June 2025: 69.4% from 670 flights
- July 2025: 63.9% from 673 flights
- August 2025: 73.8% from 685 flights
- September 2025: 56.2% from 660 flights
- October 2025: 57.6% from 695 flights
- November 2025: 73.1% from 639 flights
- December 2025: 66.2% from 557 flights
- January 2026: 69.0% from 500 flights
- February 2026: 71.2% from 503 flights
- March 2026: 66.3% from 598 flights
- April 2026: 69.9% from 641 flights
- May 2026: 76.6% from 740 flights
- June 2026: 68.3% from 751 flights
- July 2026: 66.6% from 786 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 67.9% against 75.7% in the 12 months before — declining by 7.8 percentage points.
Data and methodology
Calculated by FlyerIntel from 21,895 ORD → BOS flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed