Route reliability record
PHX→ONT
Phoenix to Ontario
- Flights
- 3,012
- Period
- September 2025 to August 2026
- Distance
- 325 mi
- Carriers
- 4
This route lands a B+, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 3,012 PHX to ONT flights, of which American Airlines flew 1,305 at 79.9% on time.
Best time to fly PHX to ONT: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 96.3% of the time and Tuesday flights 82.3%, against 76.8% for the route overall.
The US average over the same twelve months is 77.3%, 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
76.8%
Arrivals under 15 minutes late, of 2,996 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
National rate is 1.89%
Best carrier
American
79.9% on time across 1,305 flights
These figures cover 3,012 flights between September 2025 and August 2026. The median arrival is 4 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.
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Carrier by carrier
Which airline is most reliable on PHX to ONT
The choice of carrier is not cosmetic here. American Airlines arrives on time 79.9% of the time; Southwest Airlines manages 73.9%. Sample sizes sit next to every figure, because a two-point gap across 1,616 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 45 | 91.1% | 37 min | 0.00% | A+ |
| SkyWest Airlinesthin sample | 46 | 80.0% | 46 min | 2.17% | B |
| American Airlines | 1,305 | 79.9% | 68 min | 0.84% | B+ |
| Southwest Airlines | 1,616 | 73.9% | 49 min | 0.25% | C+ |
American leads Southwest by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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Best ways to make this trip
The most reliable ways to fly Phoenix to Ontario
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PHX → LAXPhoenix to Los Angeles | SkyWest Airlines | 89.4% | 90.0% | 0.71% | 5am–8am, Tue | OO 4119 10:45 |
| 2. PHX → BURPhoenix to Burbank | Envoy Air | 83.9% | 84.4% | 0.55% | 8am–11am, Wed | — |
| 3. PHX → LAXPhoenix to Los Angeles | American Airlines | 81.3% | 81.7% | 0.54% | 5am–8am, Tue | — |
| 4. PHX → LAXPhoenix to Los Angeles | Frontier Airlines | 81.0% | 82.0% | 1.20% | 5am–8am, Sat | — |
| 5. PHX → ONTPhoenix to Ontario | American Airlines | 79.2% | 79.9% | 0.84% | 5am–8am, Tue | — |
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 34 points, against 6 points between the best and worst carrier.
- 5am–8am81 flights96.3%
- 8am–11am799 flights89.3%
- 11am–2pm354 flights79.6%
- 2pm–5pm588 flights77.9%
- 5pm–8pm542 flights70.4%
- 8pm–5am648 flights61.9%
Scale runs 55% to 100%.
The 8pm–5am window is where this operation falls apart: 61.9% on time, against 96.3% 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 799 flights scheduled in it.
Explore
Filter PHX to ONT by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On PHX to ONT, the best departure window is 5am–8am at 96.3% on time and the worst is 8pm–5am at 61.9%, a wide gap of 34.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am96.3%
- 8–11am89.3%
- 11am–2pm79.6%
- 2–5pm77.9%
- 5–8pm70.4%
- 8pm–5am61.9%
best all US flightsScale 55% to 100%.
Across the year
When delays peak on this route
This route's year swings by 15 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.
June is the worst month at 68.9% on time, 15 points below January, the best at 84.2%. 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. March was the busiest month here, with 288 flights.
Across the week, Tuesday is the strongest day at 82.3% on time and Friday the weakest at 72.9%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 59% of the 39,000 delay minutes carriers reported here, and the remaining four split what is left.
- 59%Late-arriving aircraft
- 34%Carrier
- 5%National Airspace System
- 1%Extreme weather
- 0%Security
59% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 39,000 reported delay minutes here, that single category outweighs weather by 41 to one. The split is drawn from 38,872 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 13,000 of the 39,000 delay minutes reported here.
Cancellations are rare at 0.53%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
6.9% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
At 325 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 82.4% on time across 3,011 flights, 6 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.
The sample behind these figures is 3,012 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 ONT 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. January runs 84.2% on time and June 68.9%, a swing of 15 points. If the dates move at all, move them out of June before you think about anything else. 2,996 completed flights over 12 months sit behind that.
Common questions
PHX to ONT questions
How often is PHX to ONT 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 23.2% of the 3,012 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PHX to ONT?
American Airlines leads at 79.9% on time across 1,305 flights. Southwest Airlines is at the other end on 73.9%, a gap of 6 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 PHX to ONT?
The 5am–8am departure window is the strongest at 96.3% on time. The 8pm–5am window is the weakest at 61.9%, 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 June delays on PHX to ONT?
June is the weakest month at 68.9% on time, compared with 84.2% in January. Across the year that is 15 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
- ONT to PHX — the return legseparate record
- Phoenix Sky Harbor International (PHX) delay statistics
- Ontario International (ONT) delay statistics
- American Airlines on PHX to ONT79.9%
- Southwest Airlines on PHX to ONT73.9%
- PHX to DEN, a related route76.7%
- DEN to ONT, a related route74.8%
- PHX to LAX, a related route82.1%
- Envoy Air on-time record91.1%
- SkyWest Airlines on-time record80.0%
- American Airlines on-time record79.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. PHX to ONT and ONT to PHX 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.