Route reliability record
DTW→BOS
Detroit to Boston
- Flights
- 2,588
- Period
- July 2025 to June 2026
- Distance
- 632 mi
- Carriers
- 4
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,588 flights, of which Delta Air Lines flew 1,710 at 74.9% on time.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.8%
Arrivals under 15 minutes late, of 2,534 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
2.09%
National rate is 1.81%
Best carrier
Delta
74.9% on time across 1,710 flights
These figures cover 2,588 flights between July 2025 and June 2026. Beyond the headline rate, 10.7% 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
Which airline is most reliable on DTW to BOS
The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 154 | 77.9% | 60 min | 0.00% | B+ |
| Delta Air Lines | 1,710 | 74.9% | 67 min | 1.81% | C |
| JetBlue Airways | 723 | 74.0% | 87 min | 3.18% | C− |
| Republic Airwaysthin sample | 1 | 0.0% | 20 min | 0.00% | F+ |
JetBlue Airways cancels 3.2% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 34 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am507 flights90.0%
- 8am–11am591 flights81.3%
- 11am–2pm170 flights79.2%
- 2pm–5pm409 flights67.1%
- 5pm–8pm450 flights55.9%
- 8pm–5am461 flights73.0%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 55.9% on time, against 90.0% 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 591 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 13 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 67.4% on time, 13 points below February, the best at 80.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 279 flights.
Across the week, Saturday is the strongest day at 83.1% on time and Sunday the weakest at 66.9%. 16 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 46,000 reported delay minutes.
- 41%National Airspace System
- 33%Carrier
- 25%Late-arriving aircraft
- 2%Extreme weather
- 0%Security
41% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 19,000 minutes out of 46,000, against a national NAS share of 21%. The split is drawn from 46,157 reported delay minutes.
Cancellations sit at 2.09% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.7% 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.
The 632 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 77.6% on time across 2,591 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,588 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 80.7% on time and July 67.4%, a swing of 13 points. If the dates move at all, move them out of July before you think about anything else. 2,534 completed flights over 12 months sit behind that.
Common questions
DTW to BOS questions
How often is DTW to BOS delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.2% of the 2,588 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on DTW to BOS?
Delta Air Lines leads at 74.9% on time across 1,710 flights. JetBlue Airways is at the other end on 74.0%, a gap of about a point. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DTW to BOS?
The 5am–8am departure window is the strongest at 90.0% on time. The 5pm–8pm window is the weakest at 55.9%, 34 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on DTW to BOS?
July is the weakest month at 67.4% on time, compared with 80.7% in February. Across the year that is 13 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BOS to DTW — the return legseparate record
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Boston Logan International (BOS) delay statistics
- Spirit Airlines on-time record77.9%
- Delta Air Lines on-time record74.9%
- JetBlue Airways on-time record74.0%
- The best time of day to fly, according to 7.04 million flight records
- Connecting flights: how much buffer the data says you need
Direction matters. DTW to BOS and BOS to DTW are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.