ONT to BWI flight delays
Ontario, CA (ONT) Baltimore, MD (BWI) · 2,283 miles
281 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
84.29%
Arrived on time
Within 15 minutes of schedule
0.36%
Cancelled
Share of scheduled flights
47 min
When late, late by
Average across delayed arrivals
9 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The two directions do not behave alike. BWI to ONT arrives on time 22 points less often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
The season swings this route hard. In June it ran 25.9 points more punctual than in March — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
Only Southwest Airlines flies this route in the published record, so there is no choice to weigh — the route's figures and the airline's are the same figures.
This is a thin route — 281 flights across the whole period. On a route this infrequent a cancellation is far more costly than the rate suggests, because the next departure may not be the same day.
Which airline should you fly on this route?
Over January 2025 – August 2026, Southwest Airlines arrived on time most often on ONT to BWI. Flights ran closest to schedule in June and worst in January.
Every airline on ONT to BWI
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 281 | 84.29% | 0.36% | 47 min | B |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
BWI to ONT Baltimore back to Ontario 62.28% on time FOther routes from Ontario
Common questions
Are flights from Ontario to Baltimore usually delayed?
84.29% of flights on the ONT to BWI route arrived within 15 minutes of schedule, so roughly 2 in every ten arrived late. That is better than the average route in this record.
Which airlines fly from Ontario to Baltimore?
Only Southwest Airlines appears in the published record on this route, with 281 flights and 84.29% arriving on time.
How often are ONT to BWI flights cancelled?
0.36% of scheduled flights did not operate — about 4 in every thousand. That is in the normal range.
What is the best month to fly Ontario to Baltimore?
June, when 100% of flights arrived on time. The worst was March at 74.1%.
When ONT to BWI flights are late, how late are they?
About 47 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on ONT to BWI during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →