Route reliability record
BWI→ATL
Baltimore to Atlanta
- Flights
- 5,431
- Period
- June 2025 to May 2026
- Distance
- 577 mi
- Carriers
- 4
This route lands a B, 2 points better than the national rate of 77.4%. About one flight in five arrive 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 5,431 flights, of which Delta Air Lines flew 2,838 at 84.3% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 84.3% on time across 2,838 flights.
Key figures
On time
79.4%
Arrivals under 15 minutes late, of 5,313 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.99%
National rate is 1.80%
Best carrier
Delta
84.3% on time across 2,838 flights
These figures cover 5,431 flights between June 2025 and May 2026. The median arrival is 7 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 BWI to ATL
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 84.3% of the time; Frontier Airlines manages 66.5%. Sample sizes sit next to every figure, because a two-point gap across 848 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 2,838 | 84.3% | 84 min | 2.18% | B |
| Spirit Airlinesthin sample | 165 | 82.9% | 60 min | 0.61% | B+ |
| Southwest Airlines | 1,580 | 77.0% | 62 min | 1.39% | B |
| Frontier Airlines | 848 | 66.5% | 72 min | 2.71% | C |
The spread between Delta and Frontier 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.
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 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,136 flights85.4%
- 8am–11am1,289 flights89.0%
- 11am–2pm833 flights81.1%
- 2pm–5pm868 flights78.8%
- 5pm–8pm1,149 flights65.2%
- 8pm–5am156 flights55.2%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 55.2% on time, against 89.0% for the 8am–11am 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.
Across the year
When delays peak on this route
This route's year swings by 25 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 64.5% on time, 25 points below February, the best at 89.4%. 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.
Across the week, Wednesday is the strongest day at 85.0% on time and Sunday the weakest at 75.0%. 10 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 80,000 reported delay minutes.
- 39%Late-arriving aircraft
- 32%Carrier
- 25%National Airspace System
- 4%Extreme weather
- 0%Security
39% 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 80,000 reported delay minutes here, that single category outweighs weather by 11 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 practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.0% on time here.
Cancellations sit at 1.99% against a national 1.80%, which is ordinary. Diversions add another 0.18%.
Connections and stage length
What a delay here actually costs
7.5% of arrivals land an hour or more late, close to the national 8.2%. 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 are the a little over an hour kind, which a normal layover absorbs.
The 577 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 is a different operation and performs like one: it runs 73.9% on time across 5,430 flights, 6 points below 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 5,431 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 89.4% on time and June 64.5%, a swing of 25 points. If the dates move at all, move them out of June before you think about anything else.
Common questions
BWI to ATL questions
How often is BWI to ATL delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.6% of the 5,431 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on BWI to ATL?
Delta Air Lines leads at 84.3% on time across 2,838 flights. Frontier Airlines is at the other end on 66.5%, a gap of 18 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 BWI to ATL?
The 8am–11am departure window is the strongest at 89.0% on time. The 8pm–5am window is the weakest at 55.2%, 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 BWI to ATL?
June is the weakest month at 64.5% on time, compared with 89.4% in February. Across the year that is 25 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
- ATL to BWI — the return legseparate record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Delta Air Lines on-time record84.3%
- Spirit Airlines on-time record82.9%
- Southwest Airlines on-time record77.0%
- 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. BWI to ATL and ATL to BWI 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, June 2025 to May 2026. Updated monthly. How this data is collected.