Route profile
BOS→BWI
Flight reliability, delays and best times to fly from Boston to Baltimore, 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 45% of comparable major US routes (4,598 compared)
Calculated from 12,072 flights. How this is calculated
BOS → BWI arrives on time 79.8% of the time; the return trip, BWI → BOS, arrives on time 74.8% of the time, a 5.0-point gap between the two directions of the same city pair.
BOS → BWI spends 24.1 minutes on the ground on a 369-mile trip: 17.6 minutes from pushback to wheels-up at BOS and 6.5 minutes from touchdown to gate at BWI.
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 93% of 4,023 comparable routes.
91.7% on time for 5–9 AM departures, against 59.6% for 6–9 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.
Why BOS → BWI flights are cancelled
July 2023 – July 2026
BOS → BWI cancelled 237 of 12,072 scheduled flights — about 1 in every 51. The reason filed most often was extreme weather, 54.9% of the cancellations coded on this route — about 1 in every 93 scheduled flights.
Share of cancellations
Of 237 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.
130 cancellations, 54.9% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
70 cancellations, 29.5% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
37 cancellations, 15.6% 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.
237 coded cancellations were recorded on BOS → BWI; the section appears from 50.
When it goes wrong
July 2023 – July 2026
44 min late
against a median of 8 min early
Percentiles over 12,072 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at BWI after arriving from BOS.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 34% | Likely to miss |
| 45 min | 20% | High risk |
| 60 min | 13% | Some risk |
| 90 min | 7.3% | Some risk |
| 120 min | 4.5% | Low 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 1.96% of the time and diverts 0.13% of the time, which a late arrival never shows up in.
Chance of missing is the share of 11,819 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 44 minutes late (90th-percentile gate arrival delay), over 12,072 operations.
Any other layover length: connection checker.
Best time to fly
BOS → BWI flights departing 5–9 AM arrived on time 91.7% of the time, against 59.6% for 6–9 PM departures, a gap of 32.1 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 95.5% on time from 772 flights
- 6 AM: 90.8% on time from 1,152 flights
- 7 AM: 90.4% on time from 643 flights
- 8 AM: 90.8% on time from 961 flights
- 9 AM: 92.5% on time from 708 flights
- 10 AM: 89.3% on time from 561 flights
- 11 AM: 86.0% on time from 431 flights
- 12 PM: 86.9% on time from 651 flights
- 1 PM: 85.8% on time from 868 flights
- 2 PM: 82.3% on time from 575 flights
- 3 PM: 76.4% on time from 631 flights
- 4 PM: 62.1% on time from 483 flights
- 5 PM: 69.6% on time from 1,204 flights
- 6 PM: 66.2% on time from 610 flights
- 7 PM: 55.6% on time from 605 flights
- 8 PM: 56.8% on time from 584 flights
- 9 PM: 55.1% on time from 448 flights
- 10 PM: 70.4% on time from 184 flights
- 11 PM: too few flights to score
Why BOS → BWI runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow 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 BOS → BWI. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on BOS → BWI, at 53.3%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 91.7% of the time and 6–9 PM departures 59.6%.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of BOS to BWI: 3.9 times the normal rate at BOS and 4.8 times at BWI. Cancelled in bad weather against normal hours: BOS 5.3% against 1.4%, BWI 4.7% against 1.0%. 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 | BOS | BWI |
|---|---|---|
| Cancelled in bad weather | 5.3% | 4.7% |
| Cancelled in normal hours | 1.4% | 1.0% |
| Arrived on time, bad weather | 65.1% | 65.5% |
| Arrived on time, normal hours | 79.7% | 77.5% |
| Departures in bad weather | 60,840 | 30,451 |
Of the carriers on this route, Southwest Airlines (3.6% cancelled against 5.3% for the other carriers at BOS) cancelled the fewest departures from BOS in bad weather and Spirit Airlines (7.8% cancelled against 4.4% for the other carriers at BOS) the most.
This route’s airlines in bad weather at BOS
All departures from BOS| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| Southwest Airlines | 2,809 | 3.6%below the others | 5.3% |
| JetBlue | 17,332 | 5.4%about level | 5.1% |
| Republic Airways | 12,581 | 8.1%above the others | 5.0% |
| Spirit Airlines | 2,112 | 7.8%above the others | 4.4% |
These are airport figures, not route figures: every scheduled departure from BOS and BWI, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from BOS on every route.
Weather source and limits. In full: BOS (airlines), BWI, 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 | 7,601 | 78.6% | 1.62% | -6 min | 7.6% |
| Republic Airways | 2,952 | 84.1% | 2.41% | -11 min | 5.6% |
| Spirit Airlines | 940 | 75.3% | 3.19% | -6 min | 11.4% |
| JetBlue | 579 | 80.7% | 2.25% | -10 min | 8.7% |
Southwest Airlines flew 63.0% of the 12,072 flights listed. Spirit Airlines cancelled 3.19% of its flights here against 1.62% for Southwest Airlines.
Republic Airways arrived on time 8.8 percentage points more often than Spirit Airlines on this route.
Other ways to fly Boston to Washington
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| BOS→DCA Boston to Washington | 28,569 | 77.3% | 2.85% | -7 min | 52 |
| BOS→BWI this route Boston to Baltimore | 12,072 | 79.8% | 1.96% | -8 min | 64 |
BOS → BWI is the most reliable pairing for this journey at 79.8% on time, against 77.3% for BOS → DCA.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Sunday the least, a gap of 9.1 percentage points.
By month
- Jan: 86.2%
- Feb: 85.2%
- Mar: 85.1%
- Apr: 82.4%
- May: 77.5%
- Jun: 73.9%
- Jul: 69.0%
- Aug: 76.4%
- Sep: 78.4%
- Oct: 80.3%
- Nov: 86.8%
- Dec: 83.7%
July is historically the weakest month and November the strongest, a spread of 17.8 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 65.0% from 373 flights
- August 2023: 73.0% from 388 flights
- September 2023: 75.1% from 355 flights
- October 2023: 82.1% from 364 flights
- November 2023: 88.7% from 353 flights
- December 2023: 85.6% from 338 flights
- January 2024: 78.5% from 281 flights
- February 2024: 89.2% from 254 flights
- March 2024: 86.9% from 290 flights
- April 2024: 82.5% from 339 flights
- May 2024: 78.5% from 356 flights
- June 2024: 76.3% from 338 flights
- July 2024: 70.1% from 338 flights
- August 2024: 75.8% from 387 flights
- September 2024: 84.1% from 359 flights
- October 2024: 87.9% from 388 flights
- November 2024: 87.6% from 372 flights
- December 2024: 85.5% from 351 flights
- January 2025: 91.4% from 306 flights
- February 2025: 79.3% from 285 flights
- March 2025: 85.5% from 327 flights
- April 2025: 84.5% from 343 flights
- May 2025: 74.4% from 353 flights
- June 2025: 68.9% from 357 flights
- July 2025: 71.1% from 364 flights
- August 2025: 81.2% from 318 flights
- September 2025: 75.0% from 288 flights
- October 2025: 69.5% from 337 flights
- November 2025: 83.3% from 290 flights
- December 2025: 79.0% from 275 flights
- January 2026: 88.4% from 239 flights
- February 2026: 88.1% from 233 flights
- March 2026: 82.7% from 266 flights
- April 2026: 80.1% from 322 flights
- May 2026: 79.7% from 316 flights
- June 2026: 77.1% from 303 flights
- July 2026: 69.8% from 326 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 79.0% against 81.2% in the 12 months before — declining by 2.2 percentage points.
Data and methodology
Calculated by FlyerIntel from 12,072 BOS → BWI 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