Airport month record

BOSDEC

Boston Logan International in December 2025

Departures: 11,248
Month: December 2025
National, same month: 73.2%
Carriers: 11

Historical statistics for December 2025, not live status or a forecast for this year’s December. For today’s conditions at BOS, see live FAA status.

BOS in December 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 73.2%. The late ones land a little over an hour behind schedule. That rests on 11,248 flights, of which United Airlines flew 970 at 77.9% on time.

United Airlines is the most reliable of the six carriers covered here at 77.9% on time across 970 flights.

On time

68.7%

Arrivals under 15 minutes late, of 11,033 completed departures

Avg delay

71 min

Across delayed arrivals only, not all flights

Cancelled

1.69%

Nationally in December: 1.55%

Whole year

75.6%

BOS across all twelve months

These figures cover 11,248 departures from Boston Logan International in December 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

December next to BOS's other months

Against BOS's own year, December ran 7 points worse than the twelve-month rate of 75.6%, which makes it the worst of the twelve months in the data. Either side of it, November ran 78.0% on time and January 73.6%, so a trip moved by a few weeks would have landed in a better stretch.

BOS month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	12,912	70.9%	82 min	4.07%	C−
August 2025	12,461	81.4%	69 min	1.00%	B
September 2025	11,597	75.7%	73 min	1.35%	B
October 2025	12,647	73.9%	75 min	1.51%	C
November 2025	11,385	78.0%	75 min	2.76%	B
December 2025 (this page)	11,248	68.7%	71 min	1.69%	C
January 2026	10,298	73.6%	78 min	7.50%	C−
February 2026	10,232	74.8%	73 min	8.15%	C−
March 2026	12,299	74.1%	69 min	2.69%	C
April 2026	12,626	79.3%	62 min	0.31%	B+
May 2026	12,694	79.4%	60 min	0.61%	B+
June 2026	12,683	76.6%	72 min	1.77%	B

Departure window

The best time of day to leave BOS in December

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am2,356 flights78.9%
8am–11am2,314 flights73.0%
11am–2pm1,853 flights68.4%
2pm–5pm1,955 flights63.7%
5pm–8pm1,976 flights61.1%
8pm–5am794 flights57.2%

Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 57.2% on time, against 78.9% 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 2,356 flights scheduled in it.

Across the week, Wednesday is the strongest day at 79.8% on time and Sunday the weakest at 52.1%. 28 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at BOS in December

The choice of carrier is not cosmetic here. United Airlines arrives on time 77.9% of the time; JetBlue Airways manages 60.0%. Sample sizes sit next to every figure, because a two-point gap across 3,066 flights means less than a ten-point one.

Carriers at BOS in December 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
JetBlue Airways	3,066	60.0%	70 min	2.25%	D
Republic Airways	2,554	74.6%	71 min	1.80%	C
Delta Air Lines	2,241	66.9%	72 min	2.59%	C
American Airlines	1,284	76.4%	85 min	0.31%	B+
United Airlines	970	77.9%	72 min	0.31%	B+
Southwest Airlines	567	71.6%	50 min	0.53%	C+
Alaska Airlinesthin sample	198	48.7%	55 min	1.01%	F
Spirit Airlinesthin sample	127	59.8%	91 min	0.00%	D+
Envoy Airthin sample	114	69.0%	64 min	0.88%	C+
Frontier Airlinesthin sample	77	50.7%	78 min	5.19%	F−
Allegiant Airthin sample	50	78.0%	73 min	0.00%	B+

The spread between United and JetBlue is 18 points, wide enough that it should decide the booking. On a hundred trips that is 18 more arrivals inside the on-time window.

Route by route

Busiest routes out of BOS in December

Routes from BOS in December 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
BOS to DCA · Washington	689	69.9%	73 min	1.16%	C
BOS to ORD · Chicago	556	69.7%	86 min	0.72%	C+
BOS to LGA · New York	506	75.9%	87 min	5.73%	B−
BOS to MCO · Orlando	436	60.7%	85 min	1.61%	D
BOS to JFK · New York	430	70.7%	73 min	3.95%	C−
BOS to ATL · Atlanta	417	69.0%	75 min	2.64%	C
BOS to LAX · Los Angeles	381	62.1%	74 min	1.31%	D
BOS to FLL · Fort Lauderdale	366	53.1%	83 min	2.19%	F
BOS to PHL · Philadelphiathin sample	364	76.1%	80 min	1.65%	B
BOS to SFO · San Franciscothin sample	357	65.0%	68 min	0.84%	C+
BOS to CLT · Charlottethin sample	331	83.3%	60 min	0.30%	B+
BOS to DEN · Denverthin sample	301	73.5%	53 min	0.66%	C+
BOS to DFW · Dallas-Fort Worththin sample	290	71.7%	87 min	1.03%	C
BOS to MIA · Miamithin sample	278	69.9%	67 min	2.16%	C
BOS to EWR · Newarkthin sample	277	71.0%	79 min	1.81%	C
BOS to BWI · Baltimorethin sample	275	79.0%	54 min	1.09%	B
BOS to RDU · Raleighthin sample	249	69.9%	76 min	1.20%	C
BOS to TPA · Tampathin sample	247	66.8%	86 min	2.83%	C
BOS to PBI · West Palm Beachthin sample	240	53.6%	73 min	1.67%	F
BOS to RSW · Fort Myersthin sample	233	59.6%	65 min	0.86%	D+
BOS to BNA · Nashvillethin sample	202	63.8%	57 min	1.49%	D
BOS to DTW · Detroitthin sample	198	67.9%	71 min	1.01%	C
BOS to PHX · Phoenixthin sample	179	69.7%	44 min	0.56%	C+
BOS to IAH · Houstonthin sample	175	77.7%	44 min	0.00%	B+
BOS to SJU · San Juanthin sample	170	58.6%	80 min	0.59%	D+

Delay causes

What held BOS up in December

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 246,000 reported delay minutes.

Late-arriving aircraft
37%
Carrier
31%
National Airspace System
30%
Extreme weather
3%
Security
0%

37% 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 246,000 reported delay minutes here, that single category outweighs weather by 12 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 245,694 reported delay minutes.

Cancellations sit at 1.69% against a national 1.55%, which is ordinary. Diversions add another 0.22%.

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.0% of arrivals land a full hour or more behind schedule, against 10.0% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

What to do with this

Flying from BOS in December

For a December trip through BOS: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 78.9% on time, and with 12.0% of arrivals an hour or more late, a connection here deserves more slack than the same trip in August would.

Boston Logan International (BOS), the whole year
BOS in July70.9%
BOS in August81.4%
BOS in September75.7%
BOS in October73.9%
BOS in November78.0%
BOS in January73.6%
BOS in February74.8%
BOS in March74.1%
BOS in April79.3%
BOS in May79.4%
BOS in June76.6%

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