Best time to fly out of Baltimore (BWI)
The early-flight folk wisdom holds up at Baltimore/Washington Thurgood Marshall: departures in the Before 6am band left on time 92.7% of the time, against 43.9% in the 10pm–12am band. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.
Data through June 2026 · Bureau of Transportation Statistics
On-time rate by hour and day
On this page, “on time” means a departure that pushed back less than 15 minutes behind its scheduled time — the Bureau of Transportation Statistics definition, and the one airlines are held to.
| Departure time | Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|---|
| Before 6am | 93 | 95 | 92 | 95 | 94 | 89 | 91 |
| 6–8am | 90 | 92 | 92 | 92 | 89 | 89 | 90 |
| 8–10am | 83 | 87 | 88 | 86 | 84 | 83 | 84 |
| 10am–12pm | 80 | 84 | 85 | 82 | 81 | 81 | 80 |
| 12–2pm | 73 | 79 | 81 | 74 | 73 | 75 | 71 |
| 2–4pm | 65 | 68 | 69 | 64 | 64 | 66 | 63 |
| 4–6pm | 63 | 71 | 69 | 64 | 63 | 64 | 59 |
| 6–8pm | 62 | 68 | 64 | 59 | 59 | 58 | 55 |
| 8–10pm | 56 | 62 | 62 | 53 | 54 | 51 | 48 |
| 10pm–12am | 46 | 47 | 51 | 47 | 48 | 36 | 38 |
The steadiest stretch at BWI was Before 6am — 92.7% of departures left on time across 2,426 flights. The weakest was 10pm–12am at 43.9%. 6–8am departures from BWI left on time 90.5% of the time across 38,484 flights; 6–8pm departures, 60.9% across 36,089. That is a gap of 29.6 points, and it is the whole case for the early flight.
The year at BWI
July was the hard month at BWI: 57.9% of departures left on time, across 26,462 flights. November was the easy one at 80.7%. Each month pools three years of that month, so a single bad week does not decide it.
| Month | Share departures that left on time | Flights |
|---|---|---|
| January | 76.3% | 21,579 |
| February | 80% | 20,017 |
| March | 71% | 23,806 |
| April | 75.9% | 24,378 |
| May | 69% | 25,226 |
| June | 65.1% | 25,484 |
| July | 57.9% | 26,462 |
| August | 68% | 25,828 |
| September | 78.9% | 24,253 |
| October | 77.2% | 25,661 |
| November | 80.7% | 23,810 |
| December | 70.3% | 24,189 |
Airlines at BWI
Every airline with at least 100 departures from BWI, busiest first. These are that airline’s departures from this airport only — its record across the country sits on its own page.
| Airline | Left on time | Typical delay | Cancelled | Departures |
|---|---|---|---|---|
| Southwest Airlines | 69.7% | 50 min | 1.2% | 218,264 |
| Spirit Airlines | 76.5% | 76 min | 1.9% | 15,908 |
| Delta Air Lines | 84.3% | 81 min | 1.1% | 15,756 |
| United Airlines | 86.7% | 79 min | 1.3% | 11,522 |
| American Airlines | 80.1% | 99 min | 2% | 10,895 |
| Frontier Airlines | 69.5% | 97 min | 3% | 9,032 |
| Republic Airways | 83.6% | 87 min | 2.3% | 3,333 |
| Envoy Air | 80.8% | 73 min | 2.3% | 2,243 |
| Alaska Airlines | 71.1% | 48 min | 1.3% | 1,747 |
| Endeavor Air | 83.2% | 111 min | 5.4% | 930 |
| JetBlue Airways | 78.9% | 101 min | 2.4% | 579 |
| Allegiant Air | 71.7% | 94 min | 0.9% | 232 |
| PSA Airlines | 77.5% | 57 min | 1.8% | 163 |
Spirit Airlines (through May 2026) and Endeavor Air (through December 2024) stopped filing before June 2026. Their rows cover a shorter run of months than the rest of the table, so their figures are not set against the others anywhere on this page.
What delays out of BWI were put down to
Airlines file a reason with every arrival running 15 minutes late or more. Across 68,310 flights that departed BWI and ran 15 minutes late or more, the delay minutes break down with 39.9% put down to late-arriving aircraft and 34.7% to airline operations.
- Late-arriving aircraft 39.9%
- Airline operations 34.7%
- Air traffic & airport volume 20.8%
- Severe weather 4.2%
- Security 0.3%
Late-arriving aircraft is the knock-on category: the plane came in late, so it went out late again. It is why a 7am problem in Newark is still a problem in Denver at dinnertime, and why it is usually the biggest slice on the bar.
If you are connecting through BWI
Of 290,691 scheduled arrivals into BWI, 79% reached the gate less than 15 minutes behind schedule. Of the 56,574 arrivals that ran late, 59.8% were no more than 45 minutes behind — which is the difference between a tight connection and a new boarding pass.
Work out a specific layover — pick the airport and the minutes you have, and the tool reads the same arrival records back as a share.
Busiest routes out of BWI
Ranked by flights, with the share that arrived on time at the far end. Where a route carries enough flights for a page of its own the chip goes there; otherwise it goes to the destination airport.
- ATL 79.1% on time · 17,567 flights
- MCO 75.1% on time · 15,506 flights
- BOS 74.8% on time · 11,785 flights
- FLL 75.2% on time · 10,795 flights
- CLT 77.6% on time · 9,336 flights
- DEN 76.5% on time · 9,105 flights
- TPA 77.1% on time · 9,028 flights
- ORD 79.3% on time · 8,100 flights
- MIA 74.4% on time · 7,186 flights
- DTW 80% on time · 6,285 flights
BWI in one number
Baltimore/Washington Thurgood Marshall (BWI)
Rank 24 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: July.
Questions about BWI
- What is the best time of day to fly out of Baltimore/Washington Thurgood Marshall?
- Before 6am. Departures in that band left on time 92.7% of the time across 2,426 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 10pm–12am band was the weakest at 43.9%.
- Is the early flight out of BWI really more reliable?
- 6–8am departures from BWI left on time 90.5% of the time across 38,484 flights; 6–8pm departures, 60.9% across 36,089. That is a gap of 29.6 points, and it is the whole case for the early flight.
- What is the worst month to fly out of BWI?
- July: 57.9% of the departures that flew left on time, with 26,462 scheduled. November was the other end of the year at 80.7%. Each figure pools three years of that calendar month.
- Which airline is most on time at BWI?
- United Airlines — 86.7% of its 11,522 departures from BWI left on time. Frontier Airlines sat at the other end at 69.5% over 9,032 flights. Only airlines with at least 100 departures here are ranked. Airlines that stopped filing before June 2026 are left out of the ranking — their figures cover a shorter run of months than the rest of the table.
- How often are flights cancelled at BWI?
- 1.3% of scheduled departures were cancelled over July 2023 through June 2026. Cancellations are counted against everything scheduled, not against everything that flew — a rate that looks small still adds up to real people in a rebooking line.