Route profile
MDW→BOS
Flight reliability, delays and best times to fly from Chicago to Boston, 861 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 24% of comparable major US routes (4,598 compared)
Calculated from 4,257 flights. How this is calculated
MDW → BOS arrives on time 71.5% of the time; the return trip, BOS → MDW, arrives on time 75.4% of the time, a 3.9-point gap between the two directions of the same city pair.
MDW → BOS spends 20.5 minutes on the ground on an 861-mile trip: 14.6 minutes from pushback to wheels-up at MDW and 6.0 minutes from touchdown to gate at BOS.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
On-time performance swings unusually widely by time of day here, wider than 99% of 4,023 comparable routes.
91.4% on time for 5–9 AM departures, against 53.8% for 3–6 PM.
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 4,023 in the comparison.
What sets this route apart
Where MDW to BOS differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
MDW to BOS struggles most at 4 PM: 46.5% of its flights scheduled then arrive on time, 22.1 points behind the 68.6% on routes of similar length at the same hour. Against all other routes the gap is 24.2 points.
Thursday is the day MDW to BOS slips furthest against routes of similar length, 66.4% on time where they average 76.5%, 10.1 points lower. Against all other routes the gap is 10.4 points.
In September, MDW to BOS runs 15.7 points below routes of similar length, 66.7% on time to 82.4%. Against all other routes the gap is 15.7 points.
Southwest Airlines’ flights on MDW to BOS arrive on time 71.5% of the time, 5.1 points below the 76.6% it manages on its routes of similar length. Against all other routes the gap is 5.9 points.
MDW to BOS against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 4 PM departures | 46.5% | routes of similar length | 68.6% | −22.1 pts | 187 here, 149,071 there |
| Weekday: Thursday | 66.4% | routes of similar length | 76.5% | −10.1 pts | 646 here, 401,603 there |
| Month: September | 66.7% | routes of similar length | 82.4% | −15.7 pts | 396 here, 212,616 there |
| Airline: Southwest Airlines | 71.5% | routes of similar length | 76.6% | −5.1 pts | 4,209 here, 715,429 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 861 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
59 min late
against a median of 1 min early
MDW → BOS has an average that understates its risk: a typical arrival is 1 min early, but the worst tenth are 60 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 4,257 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at BOS after arriving from MDW.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 47% | Likely to miss |
| 45 min | 27% | High risk |
| 60 min | 19% | High risk |
| 90 min | 9.6% | Some risk |
| 120 min | 5.6% | 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 1.01% of the time and diverts 0.12% of the time, which a late arrival never shows up in.
Chance of missing is the share of 4,209 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 59 minutes late (90th-percentile gate arrival delay), over 4,257 operations.
Any other layover length: connection checker.
Best time to fly
MDW → BOS flights departing 5–9 AM arrived on time 91.4% of the time, against 53.8% for 3–6 PM departures, a gap of 37.6 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 94.8% on time from 191 flights
- 6 AM: 93.7% on time from 284 flights
- 7 AM: 90.9% on time from 310 flights
- 8 AM: 88.0% on time from 354 flights
- 9 AM: 87.0% on time from 343 flights
- 10 AM: 86.9% on time from 145 flights
- 11 AM: too few flights to score
- 12 PM: 65.0% on time from 278 flights
- 1 PM: 62.2% on time from 296 flights
- 2 PM: 61.5% on time from 303 flights
- 3 PM: 50.3% on time from 198 flights
- 4 PM: 46.5% on time from 189 flights
- 5 PM: 63.9% on time from 205 flights
- 6 PM: 64.3% on time from 436 flights
- 7 PM: 55.6% on time from 272 flights
- 8 PM: 61.5% on time from 244 flights
- 9 PM to 11 PM: too few flights to score
Why MDW → BOS runs late
July 2023 – July 2026
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
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 MDW → BOS. Only delays of 15 minutes or more are attributed.
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 4,257 | 71.5% | 1.01% | -1 min | 9.8% |
Other ways to fly Chicago to Boston
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| ORD→BOS Chicago to Boston | 21,895 | 72.4% | 1.92% | -5 min | 46 |
| MDW→BOS this route Chicago to Boston | 4,257 | 71.5% | 1.01% | -1 min | 55 |
MDW → BOS is the most reliable pairing for this journey at 71.5% on time, against 72.4% for ORD → BOS.
Flying to BOS from the Chicago area? Compare MDW, ORD for BOS, with the same test for what counts as a real difference.
Weekly and seasonal patterns
By day of week
Saturday is historically the most reliable day and Thursday the least, a gap of 12.7 percentage points.
By month
- Jan: 80.6%
- Feb: 83.5%
- Mar: 69.1%
- Apr: 81.3%
- May: 69.0%
- Jun: 61.8%
- Jul: 65.2%
- Aug: 69.7%
- Sep: 66.7%
- Oct: 75.7%
- Nov: 81.7%
- Dec: 73.9%
June is historically the weakest month and February the strongest, a spread of 21.7 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 59.5% from 136 flights
- August 2023: 68.7% from 147 flights
- September 2023: 62.9% from 133 flights
- October 2023: 76.1% from 142 flights
- November 2023: too few flights to score (100)
- December 2023: too few flights to score (101)
- January 2024: too few flights to score (83)
- February 2024: too few flights to score (75)
- March 2024: too few flights to score (97)
- April 2024: too few flights to score (102)
- May 2024: too few flights to score (108)
- June 2024: 61.3% from 160 flights
- July 2024: 69.2% from 170 flights
- August 2024: 66.9% from 144 flights
- September 2024: 80.9% from 136 flights
- October 2024: 88.5% from 139 flights
- November 2024: too few flights to score (89)
- December 2024: too few flights to score (91)
- January 2025: too few flights to score (71)
- February 2025: too few flights to score (66)
- March 2025: too few flights to score (83)
- April 2025: too few flights to score (94)
- May 2025: too few flights to score (101)
- June 2025: 63.7% from 157 flights
- July 2025: 67.9% from 172 flights
- August 2025: 73.9% from 134 flights
- September 2025: 55.5% from 128 flights
- October 2025: 62.3% from 139 flights
- November 2025: too few flights to score (88)
- December 2025: too few flights to score (90)
- January 2026: too few flights to score (69)
- February 2026: too few flights to score (63)
- March 2026: too few flights to score (113)
- April 2026: too few flights to score (119)
- May 2026: 71.5% from 123 flights
- June 2026: 60.3% from 143 flights
- July 2026: 62.6% from 151 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 66.8% against 75.4% in the 12 months before — declining by 8.6 percentage points.
Data and methodology
Calculated by FlyerIntel from 4,257 MDW → 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