Route profile
SJU→ATL
Flight reliability, delays and best times to fly from San Juan to Atlanta, 1,547 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 65% of comparable major US routes (4,598 compared)
Calculated from 6,609 flights. How this is calculated
SJU → ATL arrives on time 81.3% of the time; the return trip, ATL → SJU, arrives on time 74.9% of the time, a 6.4-point gap between the two directions of the same city pair.
SJU → ATL spends 28.6 minutes on the ground on a 1,547-mile trip: 16.2 minutes from pushback to wheels-up at SJU and 12.4 minutes from touchdown to gate at ATL.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
The airline matters unusually much on this route, a wider carrier-to-carrier gap than 100% of 2,692 comparable routes.
Delta Air Lines arrived on time 87.7% of the time, against 56.9% for Frontier Airlines, flying the exact same route.
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 2,692 in the comparison.
What sets this route apart
Where SJU to ATL differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SJU to ATL is at its best against routes of similar length for flights scheduled at 7 PM: 84.4% arrive on time, 17.9 points ahead of the 66.5% those routes manage at that hour. Against all other routes the gap is 16.6 points.
SJU to ATL holds up on Fridays better than routes of similar length do: 82.8% on time to their 76.4%, a 6.4 points lead. Against all other routes the gap is 6.6 points.
June is kinder to SJU to ATL than to routes of similar length: 81.4% on time against 71.7%, 9.7 points better. Against all other routes the gap is 8.7 points.
Frontier Airlines’ flights on SJU to ATL arrive on time 56.9% of the time, 12.7 points below the 69.6% it manages on its routes of similar length. Against all other routes the gap is 14.4 points.
Delta Air Lines does better on SJU to ATL than on its routes of similar length: 87.7% on time here, 82.4% there, 5.3 points apart. Against all other routes the gap is 6.2 points.
SJU to ATL against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 7 PM departures | 84.4% | routes of similar length | 66.5% | +17.9 pts | 141 here, 67,446 there |
| Weekday: Friday | 82.8% | routes of similar length | 76.4% | +6.4 pts | 981 here, 237,740 there |
| Month: June | 81.4% | routes of similar length | 71.7% | +9.7 pts | 565 here, 138,070 there |
| Airline: Frontier Airlines | 56.9% | routes of similar length | 69.6% | −12.7 pts | 877 here, 64,592 there |
| Airline: Delta Air Lines | 87.7% | routes of similar length | 82.4% | +5.3 pts | 4,937 here, 297,374 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 1,547 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 → ATL flights are cancelled
July 2023 – July 2026
SJU → ATL cancelled 58 of 6,609 scheduled flights — about 1 in every 114. The reason filed most often was the airline, 53.4% of the cancellations coded on this route — about 1 in every 213 scheduled flights.
Share of cancellations
Of 58 cancelled departures carrying a reason code.
What each reason means
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
31 cancellations, 53.4% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
19 cancellations, 32.8% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
6 cancellations, 10.3% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
2 cancellations, 3.4% 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.
58 coded cancellations were recorded on SJU → ATL; the section appears from 50.
When it goes wrong
July 2023 – July 2026
37 min late
against a median of 7 min early
Percentiles over 6,609 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at ATL after arriving from SJU.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 34% | Likely to miss |
| 45 min | 18% | High risk |
| 60 min | 12% | Some risk |
| 90 min | 6.1% | Some risk |
| 120 min | 3.7% | 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 0.88% of the time and diverts 0.64% of the time, which a late arrival never shows up in.
Chance of missing is the share of 6,509 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 37 minutes late (90th-percentile gate arrival delay), over 6,609 operations.
Any other layover length: connection checker.
Best time to fly
SJU → ATL flights departing 5–9 AM arrived on time 90.5% of the time, against 62.6% for 9 PM–5 AM departures, a gap of 27.9 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 88.2% on time from 534 flights
- 7 AM: 91.3% on time from 951 flights
- 8 AM: 92.9% on time from 182 flights
- 9 AM to 11 AM: too few flights to score
- 12 PM: 81.4% on time from 564 flights
- 1 PM: 86.4% on time from 418 flights
- 2 PM: 83.9% on time from 919 flights
- 3 PM: 70.0% on time from 644 flights
- 4 PM: 69.0% on time from 453 flights
- 5 PM: 77.8% on time from 943 flights
- 6 PM: 82.0% on time from 479 flights
- 7 PM: 84.4% on time from 142 flights
- 8 PM to 11 PM: too few flights to score
Why SJU → ATL 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 → ATL. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on SJU → ATL, at 41.4%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 90.5% of the time and 9 PM–5 AM departures 62.6%.
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 5,000 | 87.7% | 0.62% | -9 min | 3.7% |
| Frontier Airlines | 901 | 56.9% | 2.11% | 7 min | 17.3% |
| Spirit Airlines | 708 | 66.8% | 1.13% | 0 min | 10.4% |
Delta Air Lines flew 75.7% of the 6,609 flights listed. Frontier Airlines cancelled 2.11% of its flights here against 0.62% for Delta Air Lines.
Delta Air Lines arrived on time 30.8 percentage points more often than Frontier Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| DL1763 Delta Air Lines | 7:30 AM | 1,080 | 92.7% |
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 8.2 percentage points.
By month
- Jan: 77.6%
- Feb: 82.2%
- Mar: 80.5%
- Apr: 81.6%
- May: 79.0%
- Jun: 81.4%
- Jul: 77.1%
- Aug: 79.4%
- Sep: 86.1%
- Oct: 86.5%
- Nov: 87.0%
- Dec: 82.6%
July is historically the weakest month and November the strongest, a spread of 9.9 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 76.1% from 186 flights
- August 2023: 74.7% from 177 flights
- September 2023: 88.6% from 132 flights
- October 2023: 87.3% from 144 flights
- November 2023: 90.2% from 175 flights
- December 2023: 80.7% from 208 flights
- January 2024: 76.7% from 211 flights
- February 2024: 80.3% from 178 flights
- March 2024: 83.1% from 207 flights
- April 2024: 83.9% from 175 flights
- May 2024: 65.3% from 200 flights
- June 2024: 75.8% from 196 flights
- July 2024: 65.5% from 204 flights
- August 2024: 84.8% from 162 flights
- September 2024: too few flights to score (115)
- October 2024: 89.8% from 127 flights
- November 2024: 82.2% from 136 flights
- December 2024: 82.0% from 203 flights
- January 2025: 78.5% from 192 flights
- February 2025: 87.3% from 157 flights
- March 2025: 84.9% from 220 flights
- April 2025: 87.3% from 200 flights
- May 2025: 84.9% from 200 flights
- June 2025: 81.2% from 202 flights
- July 2025: 86.7% from 207 flights
- August 2025: 79.2% from 156 flights
- September 2025: 86.7% from 128 flights
- October 2025: 82.6% from 133 flights
- November 2025: 87.6% from 148 flights
- December 2025: 85.3% from 192 flights
- January 2026: 77.7% from 195 flights
- February 2026: 79.7% from 177 flights
- March 2026: 73.6% from 229 flights
- April 2026: 74.1% from 201 flights
- May 2026: 87.4% from 185 flights
- June 2026: 87.9% from 175 flights
- July 2026: 80.2% from 176 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 81.4% against 84.3% in the 12 months before — declining by 2.9 percentage points.
Data and methodology
Calculated by FlyerIntel from 6,609 SJU → ATL 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