Carrier route record
F9SJU→ATL
Frontier Airlines · San Juan to Atlanta
- Flights
- 383
- Period
- September 2025 to August 2026
- Share of route
- 18%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on SJU to ATL earns a D, which is as low as this site's scale goes for a reason. Only 55.0% of flights arrive inside the 15-minute window, 22 points worse than the national rate of 77.3%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 383 flights, with a median arrival 10 minutes late.
The national on-time rate over the same period is 77.3%, so Frontier on SJU to ATL runs 22 points behind the country as a whole. Across a thousand flights that is about 223 extra late arrivals.
Key figures
On time
55.0%
Arrivals under 15 minutes late, of 373 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
2.09%
National rate is 1.89%
Whole route
81.6%
Every carrier on SJU to ATL, 2,097 flights
These figures cover 383 flights between September 2025 and August 2026. Beyond the headline rate, 18.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Frontier against every carrier on SJU to ATL
Frontier flew 383 of the 2,097 flights on SJU to ATL, about 18% of it. Its 55.0% on time is 27 points worse than the route as a whole, which runs 81.6%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Delta at 90.9% to Spirit at 8.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,638 | 90.9% | 78 min | 0.85% | A+ |
| Frontier Airlines (this page) | 383 | 55.0% | 87 min | 2.09% | D |
| Spirit Airlinesthin sample | 76 | 8.6% | 66 min | 7.89% | F− |
Flight by flight
Frontier flight numbers on SJU to ATL
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against half a point between the best and worst carrier.
- 5am–8am55 flights51.9%
- 8am–11am4 flights—
- 11am–2pm19 flights—
- 2pm–5pm182 flights61.2%
- 5pm–8pm119 flights42.7%
- 8pm–5am4 flights—
Scale runs 35% to 65%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 42.7% on time, against 61.2% for the 2pm–5pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 2pm–5pm window is the busiest, with 182 flights scheduled in it.
Across the year
Frontier on SJU to ATL through the year
January is the weak month at 51.2% on time, against 64.5% in November. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. January was the busiest month here, with 44 flights.
Across the week, Wednesday is the strongest day at 67.5% on time and Tuesday the weakest at 44.4%, a spread of 23 points.
Arrival by arrival
How late Frontier on SJU to ATL runs when it is late
The 168 late arrivals split 49 under half an hour, 51 between 30 and 60 minutes, and 68 an hour or more.
- 15+ min early82 flights22.0%
- Within 15 min123 flights33.0%
- 15–29 min late49 flights13.1%
- 30–59 min late51 flights13.7%
- 1–2 hours late37 flights9.9%
- 2+ hours late31 flights8.3%
Scale runs 0% to 100%.
Share of 373 completed flights by arrival against schedule.
29 of 138 late departures made up the time and arrived on time, 21% of them. In the other direction, 59 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ATL.
The worst days
Worst days for Frontier on SJU to ATL
The latest arrival of the period was on 19 December 2025, 18 hours 59 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 December 2025 | 18 hours 59 minutes | Carrier |
| 10 January 2026 | 12 hours 6 minutes | Carrier |
| 28 February 2026 | 10 hours 6 minutes | Late-arriving aircraft |
| 6 January 2026 | 8 hours 53 minutes | Carrier |
| 4 January 2026 | 6 hours 34 minutes | Late-arriving aircraft |
Delay causes
Why Frontier runs late on this route
Late-arriving aircraft accounts for 51% of the 15,000 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Late-arriving aircraft
- 29%Carrier
- 19%National Airspace System
- 0%Extreme weather
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 15,000 reported delay minutes here, that single category outweighs weather by 51 to one. The split is drawn from 14,625 reported delay minutes.
Cancellations sit at 2.09% against a national 1.89%, which is ordinary. Diversions add another 0.52%.
Connections and stage length
What a delay here costs
18.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 1,547 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg runs 56.5% on time across 387 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 383 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Frontier on SJU to ATL
Put together: treat all of this as provisional. 383 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 55.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 373 completed flights over 12 months sit behind that.
Related
Where to go next
- SJU to ATL, every carrier
- Frontier on ATL to SJU, the return leg
- Delta Air Lines on SJU to ATL90.9%
- Frontier Airlines network-wide record
- Luis Munoz Marin International (SJU) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.