Best time to fly out of Boston Logan (BOS)

The early-flight folk wisdom holds up at Boston Logan: departures in the Before 6am band left on time 93.4% of the time, against 61.4% in the 8–10pm 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.

Share of departures that left on time, by hour band and day of week.
Departure time MonTueWedThuFriSatSun
Before 6am 92 94 95 94 93 94 92
6–8am 89 91 92 92 90 89 90
8–10am 85 88 89 88 84 85 86
10am–12pm 81 86 87 84 81 83 81
12–2pm 78 82 83 79 77 81 78
2–4pm 72 79 79 73 70 76 71
4–6pm 67 74 73 64 64 72 64
6–8pm 64 71 70 59 62 70 60
8–10pm 63 69 67 57 58 63 55
10pm–12am 64 67 74 61 65 58 59
fewer left on time more left on time

The steadiest stretch at BOS was Before 6am — 93.4% of departures left on time across 13,903 flights. The weakest was 8–10pm at 61.4%. 6–8am departures from BOS left on time 90.3% of the time across 76,891 flights; 6–8pm departures, 64.6% across 49,091. That is a gap of 25.7 points, and it is the whole case for the early flight.

The year at BOS

July was the hard month at BOS: 71% of departures left on time, across 37,998 flights. November was the easy one at 84%. Each month pools three years of that month, so a single bad week does not decide it.

Share of departures that left on time, by calendar month. Best month in green, worst in amber. The hairline sits at the overall rate, 78.3%.
Departure on-time share at BOS by calendar month
Month Share departures that left on time Flights
January 80.2% 31,056
February 79.7% 30,642
March 79.9% 35,984
April 81.4% 36,630
May 78.5% 37,900
June 76.6% 37,623
July 71% 37,998
August 75.7% 38,065
September 76.7% 35,698
October 80.4% 38,051
November 84% 34,283
December 76.7% 33,686

Airlines at BOS

Every airline with at least 100 departures from BOS, 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
JetBlue Airways 74.1% 73 min 1.8% 120,048
Republic Airways 83.4% 69 min 2.8% 87,482
Delta Air Lines 79.7% 77 min 1.2% 77,739
American Airlines 80% 95 min 1.8% 49,706
United Airlines 82.5% 80 min 1.7% 37,749
Southwest Airlines 71.6% 59 min 1.2% 20,311
Spirit Airlines 68.2% 75 min 3.1% 14,731
Alaska Airlines 77.2% 59 min 1.1% 7,487
Envoy Air 79.8% 77 min 1.8% 5,889
Frontier Airlines 73.9% 78 min 2.3% 3,488
Allegiant Air 87.7% 82 min 1.2% 1,723
SkyWest Airlines 79.6% 101 min 3.3% 703
Hawaiian Airlines 75.8% 111 min 1.1% 536

What delays out of BOS were put down to

Airlines file a reason with every arrival running 15 minutes late or more. Across 94,603 flights that departed BOS and ran 15 minutes late or more, the delay minutes break down with 38.2% put down to late-arriving aircraft and 32.8% to airline operations.

Late-arriving aircraft 38.2% Airline operations 32.8% Air traffic & airport volume 25.8% Severe weather 3.1% Security 0.1%
  • Late-arriving aircraft 38.2%
  • Airline operations 32.8%
  • Air traffic & airport volume 25.8%
  • Severe weather 3.1%
  • Security 0.1%

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 BOS

Of 427,609 scheduled arrivals into BOS, 74.1% reached the gate less than 15 minutes behind schedule. Of the 102,165 arrivals that ran late, 47.4% 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 BOS

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.

BOS in one number

Boston Logan (BOS)

Rank 12 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: July.

July 2023–June 2026 · 419,559 departures flown

78.3% of departures left on time

Questions about BOS

What is the best time of day to fly out of Boston Logan?
Before 6am. Departures in that band left on time 93.4% of the time across 13,903 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 8–10pm band was the weakest at 61.4%.
Is the early flight out of BOS really more reliable?
6–8am departures from BOS left on time 90.3% of the time across 76,891 flights; 6–8pm departures, 64.6% across 49,091. That is a gap of 25.7 points, and it is the whole case for the early flight.
What is the worst month to fly out of BOS?
July: 71% of the departures that flew left on time, with 37,998 scheduled. November was the other end of the year at 84%. Each figure pools three years of that calendar month.
Which airline is most on time at BOS?
Allegiant Air — 87.7% of its 1,723 departures from BOS left on time. Spirit Airlines sat at the other end at 68.2% over 14,731 flights. Only airlines with at least 100 departures here are ranked.
How often are flights cancelled at BOS?
1.9% 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.