Route profile
BWI→SJU
Flight reliability, delays and best times to fly from Baltimore to San Juan, 1,565 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 8% of comparable major US routes (4,598 compared)
Calculated from 4,086 flights. How this is calculated · What counts as on time
BWI → SJU arrives on time 67.7% of the time; the return trip, SJU → BWI, arrives on time 78.0% of the time, a 10.3-point gap between the two directions of the same city pair.
BWI → SJU spends 22.8 minutes on the ground on a 1,565-mile trip: 16.9 minutes from pushback to wheels-up at BWI and 5.9 minutes from touchdown to gate at SJU.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Reliability here swings unusually widely by season, a wider month-to-month spread than 94% of 3,357 comparable routes.
77.6% on time in a typical November, against 52.2% in July.
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 3,357 in the comparison.
What sets this route apart
Where BWI to SJU differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
BWI to SJU struggles most at 9 PM: 55.6% of its flights scheduled then arrive on time, 10.5 points behind the 66.1% on routes of similar length at the same hour. Against all other routes the gap is 13.9 points.
Saturday is the day BWI to SJU slips furthest against routes of similar length, 64.3% on time where they average 78.8%, 14.5 points lower. Against all other routes the gap is 14.8 points.
In August, BWI to SJU runs 18.2 points below routes of similar length, 58.1% on time to 76.3%. Against all other routes the gap is 18.4 points.
Southwest Airlines’ flights on BWI to SJU arrive on time 67.7% of the time, 7.9 points below the 75.6% it manages on its routes of similar length. Against all other routes the gap is 9.7 points.
BWI to SJU against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 9 PM departures | 55.6% | routes of similar length | 66.1% | −10.5 pts | 162 here, 32,120 there |
| Weekday: Saturday | 64.3% | routes of similar length | 78.8% | −14.5 pts | 653 here, 211,496 there |
| Month: August | 58.1% | routes of similar length | 76.3% | −18.2 pts | 356 here, 138,139 there |
| Airline: Southwest Airlines | 67.7% | routes of similar length | 75.6% | −7.9 pts | 2,455 here, 347,737 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 1,565 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.
Why BWI → SJU flights are cancelled
July 2023 – July 2026
BWI → SJU cancelled 73 of 4,086 scheduled flights — about 1 in every 56. The reason filed most often was extreme weather, 57.5% of the cancellations coded on this route — about 1 in every 97 scheduled flights.
Share of cancellations
Of 73 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.
42 cancellations, 57.5% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
25 cancellations, 34.2% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
6 cancellations, 8.2% 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.
73 coded cancellations were recorded on BWI → SJU; the section appears from 50.
When it goes wrong
July 2023 – July 2026
62 min late
against a median of 2 min late
BWI → SJU has an average that understates its risk: a typical arrival is 2 min late, 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 4,086 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SJU after arriving from BWI.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 53% | Likely to miss |
| 45 min | 31% | Likely to miss |
| 60 min | 21% | High risk |
| 90 min | 10% | Some risk |
| 120 min | 6.0% | 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 1.79% 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 4,008 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 62 minutes late (90th-percentile gate arrival delay), over 4,086 operations.
Any other layover length: connection checker.
Best time to fly
BWI → SJU flights departing 5–9 AM arrived on time 77.1% of the time, against 61.6% for 6–9 PM departures, a gap of 15.5 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 80.3% on time from 203 flights
- 7 AM: too few flights to score
- 8 AM: 76.2% on time from 697 flights
- 9 AM: 76.3% on time from 423 flights
- 10 AM: 74.1% on time from 159 flights
- 11 AM: 68.0% on time from 134 flights
- 12 PM: too few flights to score
- 1 PM: 68.3% on time from 123 flights
- 2 PM to 5 PM: too few flights to score
- 6 PM: 66.2% on time from 397 flights
- 7 PM: 61.7% on time from 660 flights
- 8 PM: 56.7% on time from 388 flights
- 9 PM: 55.6% on time from 167 flights
- 10 PM: 67.8% on time from 241 flights
- 11 PM: too few flights to score
Why BWI → SJU 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 BWI → SJU. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on BWI → SJU, at 36.1%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 77.1% of the time and 6–9 PM departures 61.6%.
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 | 2,471 | 67.7% | 0.53% | 3 min | 8.4% |
| Spirit Airlines | 1,066 | 73.1% | 2.81% | -5 min | 10.0% |
| Frontier Airlines | 549 | 56.9% | 5.46% | 8 min | 21.6% |
Southwest Airlines flew 60.5% of the 4,086 flights listed. Frontier Airlines cancelled 5.46% of its flights here against 0.53% for Southwest Airlines.
Spirit Airlines arrived on time 16.2 percentage points more often than Frontier Airlines on this route.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Monday the least, a gap of 10.2 percentage points.
By month
- Jan: 70.2%
- Feb: 73.9%
- Mar: 71.1%
- Apr: 76.7%
- May: 68.1%
- Jun: 67.2%
- Jul: 52.2%
- Aug: 58.1%
- Sep: 72.5%
- Oct: 74.6%
- Nov: 77.6%
- Dec: 65.3%
July is historically the weakest month and November the strongest, a spread of 25.4 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 43.1% from 164 flights
- August 2023: 63.4% from 158 flights
- September 2023: too few flights to score (88)
- October 2023: too few flights to score (95)
- November 2023: too few flights to score (107)
- December 2023: too few flights to score (115)
- January 2024: 64.2% from 139 flights
- February 2024: too few flights to score (108)
- March 2024: 64.6% from 128 flights
- April 2024: 80.7% from 137 flights
- May 2024: 70.8% from 122 flights
- June 2024: 71.1% from 123 flights
- July 2024: 55.0% from 124 flights
- August 2024: too few flights to score (106)
- September 2024: too few flights to score (64)
- October 2024: too few flights to score (54)
- November 2024: too few flights to score (97)
- December 2024: 72.5% from 132 flights
- January 2025: too few flights to score (101)
- February 2025: too few flights to score (90)
- March 2025: 76.8% from 142 flights
- April 2025: 75.2% from 142 flights
- May 2025: too few flights to score (113)
- June 2025: 67.9% from 134 flights
- July 2025: 55.9% from 141 flights
- August 2025: too few flights to score (103)
- September 2025: too few flights to score (70)
- October 2025: too few flights to score (61)
- November 2025: too few flights to score (75)
- December 2025: too few flights to score (115)
- January 2026: too few flights to score (108)
- February 2026: too few flights to score (91)
- March 2026: too few flights to score (109)
- April 2026: too few flights to score (111)
- May 2026: too few flights to score (90)
- June 2026: too few flights to score (109)
- July 2026: 57.3% from 120 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 66.9% against 70.1% in the 12 months before — declining by 3.2 percentage points.
Data and methodology
Calculated by FlyerIntel from 4,086 BWI → SJU 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