Best Time to Fly ISP to BWI: On-Time Stats by Hour & Airline
Long Island MacArthur → Baltimore/Washington International Thurgood Marshall
Data through July 2026 · Last updated October 18, 2026
1,235 flights were scheduled from Islip (ISP) to Baltimore (BWI) in the last 12 months, and 84.8% of those that flew arrived on time, 7.1 points above the US average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
September has been the best month (95% on time) and Monday the weakest day of the week (82%).
1.5% of flights were cancelled, versus 1.8% nationally.
ISP to BWI on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 84.8% | 65 min | 1.5% | 1,235 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ISP to BWI
On-time arrival % by scheduled departure hour (local time), 2,436 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 95.0% | 1.1% | 281 |
| 6am–7am | 95.0% | 1.1% | 449 |
| 8am–9am | 95.0% | 0.0% | 60 |
| 9am–10am | 97.4% | 1.3% | 79 |
| 10am–11am | 87.4% | 0.0% | 143 |
| 11am–12pm | 85.4% | 1.9% | 161 |
| 12pm–1pm | 82.2% | 0.3% | 304 |
| 1pm–2pm | 84.3% | 0.0% | 121 |
| 2pm–3pm | 68.5% | 0.9% | 113 |
| 3pm–4pm | 79.3% | 0.0% | 165 |
| 4pm–5pm | 81.7% | 1.8% | 224 |
| 5pm–6pm | 74.9% | 2.9% | 243 |
| 6pm–7pm | 61.6% | 1.4% | 74 |
| 7pm–8pm | Limited data | 19 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on ISP to BWI
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 88.1% | -0.4 pts | 0.0% | 42 |
| Christmas & New Year (Dec 20 - Jan 3) | 84.4% | -4.1 pts | 0.0% | 90 |
| Summer peak (Jun 15 - Aug 15) | 73.6% | -14.9 pts | 1.6% | 515 |
| All other days | 88.5% | — | 1.0% | 1,789 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).