Carrier route record

B6BOS→DEN

JetBlue Airways · Boston to Denver

Flights: 681
Period: July 2025 to June 2026
Share of route: 17%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with JetBlue Airways.

JetBlue on BOS to DEN sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 681 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,908 at 83.0% on time.

United Airlines is the most reliable of the three carriers covered here at 83.0% on time across 1,908 flights.

On time

70.9%

Arrivals under 15 minutes late, of 667 completed flights

Avg delay

60 min

Across delayed arrivals only, not all flights

Cancelled

1.76%

National rate is 1.81%

Whole route

76.5%

Every carrier on BOS to DEN, 3,899 flights

These figures cover 681 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

JetBlue against every carrier on BOS to DEN

JetBlue flew 681 of the 3,899 flights on BOS to DEN, about 17% of it. Its 70.9% on time is 6 points worse than the route as a whole, which runs 76.5%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 83.0% to Southwest at 64.8%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 83.0% of the time; Southwest Airlines manages 64.8%. Sample sizes sit next to every figure, because a two-point gap across 910 flights means less than a ten-point one.

On-time performance by carrier on BOS to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,908	83.0%	64 min	1.00%	B
Delta Air Lines	400	81.4%	46 min	1.75%	B
JetBlue Airways (this page)	681	70.9%	60 min	1.76%	C
Southwest Airlines	910	64.8%	54 min	0.88%	D+

The spread between United and Southwest 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.

Flight by flight

JetBlue flight numbers on BOS to DEN

Departure window

When JetBlue runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am78 flights84.0%
8am–11am233 flights81.4%
11am–2pm75 flights71.2%
2pm–5pm19 flights—
5pm–8pm190 flights56.5%
8pm–5am86 flights65.5%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 56.5% on time, against 84.0% 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 8am–11am window is the busiest, with 233 flights scheduled in it.

Across the year

JetBlue on BOS to DEN through the year

Darker means more delays. Figures are on-time percentages.November best, February worst

February is the weak month at 46.2% on time, against 87.5% in November. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 88 flights.

Across the week, Monday is the strongest day at 76.8% on time and Sunday the weakest at 62.4%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why JetBlue 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 12,000 reported delay minutes.

Late-arriving aircraft
38%
Carrier
32%
National Airspace System
29%
Extreme weather
2%

38% 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 12,000 reported delay minutes here, that single category outweighs weather by 19 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 11,569 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 84.0% on time here.

Cancellations sit at 1.76% against a national 1.81%, which is ordinary. Diversions add another 0.29%.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.6% of arrivals land a full hour or more behind schedule, against 8.1% 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.

At 1,754 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 68.6% on time across 682 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 681 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 JetBlue on BOS to DEN

Put together: treat all of this as provisional. 681 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 70.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 667 completed flights over 12 months sit behind that.

Where to go next

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