Route profile
BWI→BOS
Flight reliability, delays and best times to fly from Baltimore to Boston, 369 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 22% of comparable major US routes (4,598 compared)
Calculated from 12,111 flights. How this is calculated
BWI → BOS arrives on time 74.8% of the time; the return trip, BOS → BWI, arrives on time 79.8% of the time, a 5.0-point gap between the two directions of the same city pair.
BWI → BOS spends 23.5 minutes on the ground on a 369-mile trip: 16.1 minutes from pushback to wheels-up at BWI and 7.4 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 96% of 4,023 comparable routes.
92.3% on time for 5–9 AM departures, against 58.0% for 9 PM–5 AM.
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.
Why BWI → BOS flights are cancelled
July 2023 – July 2026
BWI → BOS cancelled 240 of 12,111 scheduled flights — about 1 in every 50. The reason filed most often was extreme weather, 50.4% of the cancellations coded on this route — about 1 in every 100 scheduled flights.
Share of cancellations
Of 240 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.
121 cancellations, 50.4% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
79 cancellations, 32.9% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
40 cancellations, 16.7% 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.
240 coded cancellations were recorded on BWI → BOS; the section appears from 50.
When it goes wrong
July 2023 – July 2026
57 min late
against a median of 5 min early
BWI → BOS has an average that understates its risk: a typical arrival is 5 min early, but the worst tenth are 62 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 12,111 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at BOS after arriving from BWI.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 40% | Likely to miss |
| 45 min | 25% | High risk |
| 60 min | 17% | High risk |
| 90 min | 9.2% | Some risk |
| 120 min | 5.3% | 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 1.98% of the time and diverts 0.11% of the time, which a late arrival never shows up in.
Chance of missing is the share of 11,858 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 57 minutes late (90th-percentile gate arrival delay), over 12,111 operations.
Any other layover length: connection checker.
Best time to fly
BWI → BOS flights departing 5–9 AM arrived on time 92.3% of the time, against 58.0% for 9 PM–5 AM departures, a gap of 34.3 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 94.6% on time from 1,061 flights
- 7 AM: 90.3% on time from 388 flights
- 8 AM: 90.5% on time from 1,141 flights
- 9 AM: 88.0% on time from 597 flights
- 10 AM: 86.9% on time from 1,004 flights
- 11 AM: 87.2% on time from 444 flights
- 12 PM: 74.3% on time from 339 flights
- 1 PM: 67.6% on time from 542 flights
- 2 PM: 63.3% on time from 774 flights
- 3 PM: 70.1% on time from 1,026 flights
- 4 PM: 62.0% on time from 486 flights
- 5 PM: 61.8% on time from 661 flights
- 6 PM: 57.2% on time from 632 flights
- 7 PM: 67.6% on time from 1,141 flights
- 8 PM: 69.9% on time from 564 flights
- 9 PM: 59.1% on time from 625 flights
- 10 PM: 56.8% on time from 571 flights
- 11 PM: too few flights to score
Why BWI → 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 BWI → BOS. Only delays of 15 minutes or more are attributed.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of BWI to BOS: 4.8 times the normal rate at BWI and 3.9 times at BOS. Cancelled in bad weather against normal hours: BWI 4.7% against 1.0%, BOS 5.3% against 1.4%. Flights that did leave BOS in bad weather arrived on time 65.1% of the time, against 79.7% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | BWI | BOS |
|---|---|---|
| Cancelled in bad weather | 4.7% | 5.3% |
| Cancelled in normal hours | 1.0% | 1.4% |
| Arrived on time, bad weather | 65.5% | 65.1% |
| Arrived on time, normal hours | 77.5% | 79.7% |
| Departures in bad weather | 30,451 | 60,840 |
None of the 2 carriers on this route stood clearly apart from the other carriers at BWI in bad weather. 2 more carriers fly this route but has too few bad-weather departures from BWI to compare.
This route’s airlines in bad weather at BWI
All departures from BWI| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| Southwest Airlines | 22,658 | 5.1%about level | 4.9% |
| Spirit Airlines | 1,603 | 4.6%about level | 4.1% |
These are airport figures, not route figures: every scheduled departure from BWI and BOS, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from BWI on every route.
Weather source and limits. In full: BWI (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 |
|---|---|---|---|---|---|
| Southwest Airlines | 7,637 | 72.1% | 1.70% | -1 min | 9.4% |
| Republic Airways | 2,950 | 81.8% | 2.41% | -12 min | 8.2% |
| Spirit Airlines | 945 | 73.7% | 2.65% | -8 min | 12.2% |
| JetBlue | 579 | 76.1% | 2.42% | -7 min | 10.1% |
Southwest Airlines flew 63.1% of the 12,111 flights listed.
Republic Airways arrived on time 9.7 percentage points more often than Southwest Airlines on this route.
Other ways to fly Washington to Boston
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| DCA→BOS Washington to Boston | 28,569 | 76.0% | 2.96% | -8 min | 47 |
| BWI→BOS this route Baltimore to Boston | 12,111 | 74.8% | 1.98% | -5 min | 54 |
BWI → BOS is the most reliable pairing for this journey at 74.8% on time, against 76.0% for DCA → BOS.
Flying to BOS from the Washington area? Compare BWI, DCA, IAD for BOS, with the same test for what counts as a real difference.
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 7.7 percentage points.
By month
- Jan: 81.4%
- Feb: 83.6%
- Mar: 78.7%
- Apr: 77.2%
- May: 67.0%
- Jun: 70.9%
- Jul: 65.4%
- Aug: 71.5%
- Sep: 67.2%
- Oct: 77.7%
- Nov: 84.9%
- Dec: 78.9%
July is historically the weakest month and November the strongest, a spread of 19.5 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 58.6% from 375 flights
- August 2023: 65.4% from 373 flights
- September 2023: 58.4% from 353 flights
- October 2023: 80.2% from 364 flights
- November 2023: 82.2% from 353 flights
- December 2023: 79.0% from 337 flights
- January 2024: 73.2% from 288 flights
- February 2024: 85.3% from 262 flights
- March 2024: 80.1% from 292 flights
- April 2024: 75.1% from 339 flights
- May 2024: 63.0% from 356 flights
- June 2024: 71.5% from 338 flights
- July 2024: 61.8% from 338 flights
- August 2024: 71.2% from 385 flights
- September 2024: 81.1% from 359 flights
- October 2024: 83.8% from 389 flights
- November 2024: 87.4% from 373 flights
- December 2024: 83.5% from 351 flights
- January 2025: 87.4% from 307 flights
- February 2025: 82.3% from 285 flights
- March 2025: 80.9% from 326 flights
- April 2025: 77.9% from 357 flights
- May 2025: 64.5% from 370 flights
- June 2025: 67.8% from 359 flights
- July 2025: 70.3% from 365 flights
- August 2025: 79.0% from 318 flights
- September 2025: 60.2% from 288 flights
- October 2025: 67.9% from 336 flights
- November 2025: 85.1% from 293 flights
- December 2025: 72.9% from 274 flights
- January 2026: 83.6% from 239 flights
- February 2026: 83.2% from 235 flights
- March 2026: 74.3% from 266 flights
- April 2026: 78.6% from 324 flights
- May 2026: 74.3% from 316 flights
- June 2026: 73.9% from 302 flights
- July 2026: 71.5% from 326 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 75.1% against 77.9% in the 12 months before — declining by 2.8 percentage points.
Data and methodology
Calculated by FlyerIntel from 12,111 BWI → 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