Route profile
SJU→MIA
Flight reliability, delays and best times to fly from San Juan to Miami, 1,045 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 33% of comparable major US routes (4,598 compared)
Calculated from 8,495 flights. How this is calculated · What counts as on time
SJU → MIA arrives on time 76.7% of the time; the return trip, MIA → SJU, arrives on time 76.1% of the time.
SJU → MIA spends 28.0 minutes on the ground on a 1,045-mile trip: 17.1 minutes from pushback to wheels-up at SJU and 10.9 minutes from touchdown to gate at MIA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route has stayed remarkably steady year over year, a smaller swing than 97% of 5,368 comparable routes.
78.2% on time over the most recent 12 months (2025-08 to 2026-07), against 78.0% in the 12 months before (2024-08 to 2025-07), virtually unchanged.
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 5,368 in the comparison.
What sets this route apart
Where SJU to MIA differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SJU to MIA is at its best against routes of similar length for flights scheduled at 9 PM: 78.9% arrive on time, 13.6 points ahead of the 65.3% those routes manage at that hour. Against all other routes the gap is 9.4 points.
SJU to MIA struggles most at 4 PM: 59.2% of its flights scheduled then arrive on time, 8.4 points behind the 67.6% on routes of similar length at the same hour. Against all other routes the gap is 11.5 points.
June is kinder to SJU to MIA than to routes of similar length: 78.6% on time against 71.6%, 7 points better. Against all other routes the gap is 5.9 points.
In January, SJU to MIA runs 4.2 points below routes of similar length, 72.7% on time to 76.9%. Against all other routes the gap is 6.4 points.
Spirit Airlines does better on SJU to MIA than on its routes of similar length: 77.8% on time here, 73.6% there, 4.2 points apart.
SJU to MIA against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 9 PM departures | 78.9% | routes of similar length | 65.3% | +13.6 pts | 227 here, 79,050 there |
| Hour: 4 PM departures | 59.2% | routes of similar length | 67.6% | −8.4 pts | 510 here, 154,410 there |
| Month: June | 78.6% | routes of similar length | 71.6% | +7.0 pts | 664 here, 231,249 there |
| Month: January | 72.7% | routes of similar length | 76.9% | −4.2 pts | 700 here, 222,336 there |
| Airline: Spirit Airlines | 77.8% | routes of similar length | 73.6% | +4.2 pts | 908 here, 180,353 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 1,045 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 SJU → MIA flights are cancelled
July 2023 – July 2026
SJU → MIA cancelled 71 of 8,495 scheduled flights — about 1 in every 120. The reason filed most often was extreme weather, 45.1% of the cancellations coded on this route — about 1 in every 265 scheduled flights.
Share of cancellations
Of 71 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.
32 cancellations, 45.1% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
31 cancellations, 43.7% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
8 cancellations, 11.3% 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.
71 coded cancellations were recorded on SJU → MIA; the section appears from 50.
When it goes wrong
July 2023 – July 2026
55 min late
against a median of 6 min early
SJU → MIA has an average that understates its risk: a typical arrival is 6 min early, but the worst tenth are 61 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 8,495 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at MIA after arriving from SJU.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 38% | Likely to miss |
| 45 min | 23% | High risk |
| 60 min | 16% | High risk |
| 90 min | 9.1% | Some risk |
| 120 min | 6.1% | 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 0.84% 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 8,406 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 55 minutes late (90th-percentile gate arrival delay), over 8,495 operations.
Any other layover length: connection checker.
Best time to fly
SJU → MIA flights departing 5–9 AM arrived on time 91.2% of the time, against 62.7% for 3–6 PM departures, a gap of 28.5 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 94.3% on time from 160 flights
- 6 AM: 91.3% on time from 779 flights
- 7 AM: 90.6% on time from 393 flights
- 8 AM: 89.5% on time from 163 flights
- 9 AM: 88.7% on time from 191 flights
- 10 AM: 84.3% on time from 359 flights
- 11 AM: 82.8% on time from 667 flights
- 12 PM: 83.6% on time from 766 flights
- 1 PM: 78.0% on time from 1,009 flights
- 2 PM: 73.1% on time from 571 flights
- 3 PM: 65.5% on time from 570 flights
- 4 PM: 59.2% on time from 514 flights
- 5 PM: 63.0% on time from 581 flights
- 6 PM: 65.6% on time from 589 flights
- 7 PM: 69.6% on time from 519 flights
- 8 PM: 69.8% on time from 231 flights
- 9 PM: 78.9% on time from 231 flights
- 10 PM to 11 PM: too few flights to score
Why SJU → MIA 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 SJU → MIA. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on SJU → MIA, at 53.6%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 91.2% of the time and 3–6 PM departures 62.7%.
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 |
|---|---|---|---|---|---|
| American Airlines | 6,049 | 76.6% | 0.51% | -5 min | 9.1% |
| Frontier Airlines | 1,499 | 76.9% | 1.93% | -9 min | 10.3% |
| Spirit Airlines | 922 | 77.8% | 1.19% | -7 min | 8.5% |
American Airlines flew 71.4% of the 8,470 flights listed. Frontier Airlines cancelled 1.93% of its flights here against 0.51% for American Airlines.
Carriers on this route performed within a couple of percentage points of each other.
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 7.6 percentage points.
By month
- Jan: 72.7%
- Feb: 77.8%
- Mar: 71.1%
- Apr: 76.4%
- May: 78.1%
- Jun: 78.6%
- Jul: 71.9%
- Aug: 71.9%
- Sep: 83.3%
- Oct: 84.9%
- Nov: 81.8%
- Dec: 77.4%
March is historically the weakest month and October the strongest, a spread of 13.8 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 65.6% from 245 flights
- August 2023: 75.5% from 233 flights
- September 2023: 85.2% from 187 flights
- October 2023: 89.1% from 212 flights
- November 2023: 80.8% from 213 flights
- December 2023: 77.0% from 230 flights
- January 2024: 71.6% from 222 flights
- February 2024: 72.1% from 208 flights
- March 2024: 60.4% from 243 flights
- April 2024: 76.3% from 267 flights
- May 2024: 75.5% from 279 flights
- June 2024: 68.8% from 261 flights
- July 2024: 73.1% from 284 flights
- August 2024: 67.2% from 279 flights
- September 2024: 86.4% from 221 flights
- October 2024: 89.3% from 219 flights
- November 2024: 84.0% from 232 flights
- December 2024: 72.1% from 244 flights
- January 2025: 73.9% from 245 flights
- February 2025: 80.1% from 227 flights
- March 2025: 75.0% from 247 flights
- April 2025: 79.3% from 222 flights
- May 2025: 79.9% from 209 flights
- June 2025: 81.5% from 207 flights
- July 2025: 71.6% from 216 flights
- August 2025: 74.0% from 210 flights
- September 2025: 77.4% from 168 flights
- October 2025: 74.3% from 176 flights
- November 2025: 80.5% from 211 flights
- December 2025: 82.8% from 258 flights
- January 2026: 72.5% from 250 flights
- February 2026: 81.0% from 207 flights
- March 2026: 77.1% from 278 flights
- April 2026: 73.9% from 238 flights
- May 2026: 79.6% from 216 flights
- June 2026: 87.4% from 214 flights
- July 2026: 77.7% from 217 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 78.2% against 78.0% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 8,495 SJU → MIA 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