Route reliability record
BOS→PHX
Boston to Phoenix
- Flights
- 2,024
- Period
- July 2025 to June 2026
- Distance
- 2,300 mi
- Carriers
- 3
This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,024 BOS to PHX flights, of which American Airlines flew 1,316 at 79.9% on time.
Best time to fly BOS to PHX: a 5am–8am departure, ideally on a Monday. Flights in that window arrived on time 87.9% of the time and Monday flights 79.7%, against 76.7% for the route overall.
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
76.7%
Arrivals under 15 minutes late, of 1,984 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
1.73%
National rate is 1.81%
Best carrier
American
79.9% on time across 1,316 flights
These figures cover 2,024 flights between July 2025 and June 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on BOS to PHX
The choice of carrier is not cosmetic here. American Airlines arrives on time 79.9% of the time; Delta Air Lines manages 69.1%. Sample sizes sit next to every figure, because a two-point gap across 428 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 1,316 | 79.9% | 77 min | 1.60% | B |
| JetBlue Airwaysthin sample | 280 | 73.0% | 69 min | 2.14% | C |
| Delta Air Lines | 428 | 69.1% | 57 min | 1.87% | C |
American leads Delta by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on BOS to PHX
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Boston to Phoenix
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BOS → PHXBoston to Phoenix | American Airlines | 78.6% | 79.9% | 1.60% | 5am–8am, Sat | AA 1057 12:25 |
| 2. BOS → PHXBoston to Phoenix | Delta Air Lines | 67.8% | 69.1% | 1.87% | 8am–11am, Mon | DL 514 17:55 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 24 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am358 flights87.9%
- 8am–11am600 flights79.5%
- 11am–2pm363 flights78.5%
- 2pm–5pm137 flights78.4%
- 5pm–8pm552 flights64.3%
- 8pm–5am14 flights—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.3% on time, against 87.9% 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 8am–11am window is the busiest, with 600 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 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 68.4% on time, 18 points below March, the best at 86.3%. 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. April was the busiest month here, with 211 flights.
Across the week, Monday is the strongest day at 79.7% on time and Friday the weakest at 72.5%. 7 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 32,000 reported delay minutes.
- 38%Carrier
- 38%Late-arriving aircraft
- 21%National Airspace System
- 3%Extreme weather
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 32,000 reported delay minutes here, that single category outweighs weather by 13 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 32,460 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 12,000 of the 32,000 delay minutes reported here.
Cancellations sit at 1.73% against a national 1.81%, which is ordinary. Diversions add another 0.25%.
Connections and stage length
What a delay here actually costs
7.0% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
At 2,300 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 77.3% on time across 2,022 flights, within half a point 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 2,024 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.
Work out the risk of missing a connection in PHX after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 86.3% on time and July 68.4%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 1,984 completed flights over 12 months sit behind that.
Common questions
BOS to PHX questions
How often is BOS to PHX delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.3% of the 2,024 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 BOS to PHX?
American Airlines leads at 79.9% on time across 1,316 flights. Delta Air Lines is at the other end on 69.1%, a gap of 11 points. 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 BOS to PHX?
The 5am–8am departure window is the strongest at 87.9% on time. The 5pm–8pm window is the weakest at 64.3%, 24 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 BOS to PHX?
July is the weakest month at 68.4% on time, compared with 86.3% in March. Across the year that is 18 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
- PHX to BOS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- American Airlines on BOS to PHX79.9%
- JetBlue Airways on BOS to PHX73.0%
- Delta Air Lines on BOS to PHX69.1%
- BOS to DCA, a related route74.0%
- DEN to PHX, a related route75.7%
- BOS to ORD, a related route72.7%
- American Airlines on-time record79.9%
- JetBlue Airways on-time record73.0%
- Delta Air Lines on-time record69.1%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. BOS to PHX and PHX to BOS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.