Carrier route record

F9SJU→BWI

Frontier Airlines · San Juan to Baltimore

Flights: 157
Period: July 2025 to June 2026
Share of route: 13%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.

Frontier on SJU to BWI sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land roughly 55 minutes behind schedule. That rests on 157 flights, with a median arrival right on schedule.

The national on-time rate over the same period is 77.6%, so Frontier on SJU to BWI runs 8 points behind the country as a whole. Across a thousand flights that is about 82 extra late arrivals.

On time

69.4%

Arrivals under 15 minutes late, of 147 completed flights

Avg delay

53 min

Across delayed arrivals only, not all flights

Cancelled

5.10%

National rate is 1.81%

Whole route

77.9%

Every carrier on SJU to BWI, 1,184 flights

These figures cover 157 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Frontier against every carrier on SJU to BWI

Frontier flew 157 of the 1,184 flights on SJU to BWI, about 13% of it. Its 69.4% on time is 9 points worse than the route as a whole, which runs 77.9%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Southwest at 80.3% to Frontier at 69.4%. 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.

On-time performance by carrier on SJU to BWI
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	822	80.3%	48 min	0.97%	B+
Spirit Airlinesthin sample	205	74.3%	106 min	6.34%	C−
Frontier Airlines (this page)thin sample	157	69.4%	53 min	5.10%	C−

Departure window

When Frontier runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 157 flights.

5am–8am44 flights76.9%
8am–11am31 flights—
11am–2pm12 flights—
2pm–5pm62 flights72.9%
5pm–8pm6 flights—
8pm–5am2 flights—

Scale runs 65% to 80%. Rows with fewer than 30 flights show a dash.

The early departures do better, though not dramatically: 76.9% on time for the 5am–8am window against 72.9% for 2pm–5pm. Worth taking if the schedule allows, not worth an extra connection. The 2pm–5pm window is the busiest, with 62 flights scheduled in it.

Across the year

Frontier on SJU to BWI through the year

Jul–Sep 202536 flights63.6%
Oct–Dec 202532 flights80.0%
Jan–Mar 202631 flights—
Apr–Jun 202658 flights70.2%

Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 69.4% on time across 157 flights.

Frontier on SJU to BWI did not run the same all year. Its best quarter was Oct–Dec 2025 at 80.0% on time and its weakest Jul–Sep 2025 at 63.6%, a swing of 16 points on roughly 52 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 2,386 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
52%
National Airspace System
29%
Carrier
20%

52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 2,386 reported delay minutes here, that single category outweighs weather by 52 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 2,386 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 76.9% on time here.

Cancellations run at 5.10%, against 1.81% nationally. That is about one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

7.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.

At 1,565 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 is a different operation and performs like one: it runs 52.7% on time across 157 flights, 17 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 17 points of difference.

One caution: this is a thin sample. 157 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 BWI

Put together: the delay figures matter less here than the 5.10% cancellation rate. A late arrival costs you roughly 55 minutes; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 147 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures