Carrier route record
WNISP→MCO
Southwest Airlines · Islip to Orlando
- Flights
- 666
- Period
- September 2025 to August 2026
- Share of route
- 46%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on ISP to MCO sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 666 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.3%, so Southwest on ISP to MCO runs 5 points behind the country as a whole. Across a thousand flights that is about 45 extra late arrivals.
Key figures
On time
72.8%
Arrivals under 15 minutes late, of 654 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
1.50%
National rate is 1.89%
Whole route
74.4%
Every carrier on ISP to MCO, 1,442 flights
These figures cover 666 flights between September 2025 and August 2026. Beyond the headline rate, 8.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Southwest against every carrier on ISP to MCO
Southwest flew 666 of the 1,442 flights on ISP to MCO, about 46% of it. Its 72.8% on time is 2 points worse than the route as a whole, which runs 74.4%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from JetBlue at 76.7% to Southwest at 72.8%. 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 |
|---|---|---|---|---|---|
| JetBlue Airways | 416 | 76.7% | 85 min | 1.68% | B |
| Frontier Airlinesthin sample | 360 | 74.9% | 86 min | 2.78% | C |
| Southwest Airlines (this page) | 666 | 72.8% | 59 min | 1.50% | C |
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 Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 39 points, against half a point between the best and worst carrier.
- 5am–8am300 flights88.6%
- 8am–11am46 flights81.8%
- 11am–2pm47 flights77.8%
- 2pm–5pm90 flights58.4%
- 5pm–8pm183 flights50.0%
- 8pm–5am—
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 50.0% on time, against 88.6% for the 5am–8am 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 5am–8am window is the busiest, with 300 flights scheduled in it.
Across the year
Southwest on ISP to MCO through the year
October is the best month on the calendar at 85.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 66 flights.
Across the week, Tuesday is the strongest day at 79.7% on time and Friday the weakest at 65.6%, a spread of 14 points.
Arrival by arrival
How late Southwest on ISP to MCO runs when it is late
The 178 late arrivals split 70 under half an hour, 51 between 30 and 60 minutes, and 57 an hour or more.
- 15+ min early115 flights17.6%
- Within 15 min361 flights55.2%
- 15–29 min late70 flights10.7%
- 30–59 min late51 flights7.8%
- 1–2 hours late37 flights5.7%
- 2+ hours late20 flights3.1%
Scale runs 0% to 100%.
Share of 654 completed flights by arrival against schedule.
49 of 180 late departures made up the time and arrived on time, 27% of them. In the other direction, 47 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 MCO.
The worst days
Worst days for Southwest on ISP to MCO
The latest arrival of the period was on 14 May 2026, 5 hours 55 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across May, August, July and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 May 2026 | 5 hours 55 minutes | Carrier |
| 3 August 2026 | 5 hours 24 minutes | Late-arriving aircraft |
| 18 July 2026 | 5 hours 17 minutes | Extreme weather |
| 17 March 2026 | 4 hours 27 minutes | Carrier |
| 20 August 2026 | 4 hours 27 minutes | Extreme weather |
Delay causes
Why Southwest runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 11,000 reported delay minutes.
- 34%Late-arriving aircraft
- 31%Carrier
- 26%National Airspace System
- 9%Extreme weather
- 0%Security
34% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 4 to one. The split is drawn from 10,571 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 88.6% on time here.
Cancellations sit at 1.50% against a national 1.89%, which is ordinary. Diversions add another 0.30%.
Connections and stage length
What a delay here costs
8.7% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 971 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 67.3% on time across 665 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 666 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 Southwest on ISP to MCO
Put together: treat all of this as provisional. 666 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 72.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 654 completed flights over 12 months sit behind that.
Related
Where to go next
- ISP to MCO, every carrier
- Southwest on MCO to ISP, the return leg
- JetBlue Airways on ISP to MCO76.7%
- Frontier Airlines on ISP to MCO74.9%
- Southwest Airlines network-wide record
- Orlando International (MCO) 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.