Route reliability record
MDW→BWI
Chicago to Baltimore
- Flights
- 1,852
- Period
- July 2025 to June 2026
- Distance
- 611 mi
- Carriers
- 2
This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,852 MDW to BWI flights, with a median arrival 4 minutes early.
Best time to fly MDW to BWI: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 93.0% of the time and Saturday flights 87.4%, against 78.9% 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
78.9%
Arrivals under 15 minutes late, of 1,796 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
2.75%
National rate is 1.81%
Best carrier
Southwest
78.9% on time across 1,768 flights
These figures cover 1,852 flights between July 2025 and June 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.
Carrier by carrier
Which airline is most reliable on MDW to BWI
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 84 | 79.5% | 80 min | 1.19% | B |
| Southwest Airlines | 1,768 | 78.9% | 59 min | 2.83% | B |
Best ways to make this trip
The most reliable ways to fly Chicago to Baltimore
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. MDW → BWIChicago to Baltimore | Southwest Airlines | 76.7% | 78.9% | 2.83% | 5am–8am, Sat (route) | — |
| 2. ORD → IADChicago to Washington | United Airlines | 73.6% | 74.1% | 0.68% | 5am–8am, Tue | — |
| 3. ORD → BWIChicago to Baltimore | Envoy Air | 73.5% | 76.4% | 3.77% | 5am–8am, Sat | — |
| 4. ORD → BWIChicago to Baltimore | United Airlines | 70.1% | 71.1% | 1.39% | 5am–8am, Thu | — |
| 5. ORD → DCAChicago to Washington | United Airlines | 69.3% | 70.6% | 1.80% | 5am–8am, Sat | UA 1077 06:00 |
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 31 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am436 flights93.0%
- 8am–11am334 flights87.4%
- 11am–2pm317 flights84.4%
- 2pm–5pm186 flights70.6%
- 5pm–8pm381 flights61.9%
- 8pm–5am198 flights64.1%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.9% on time, against 93.0% 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 5am–8am window is the busiest, with 436 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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 64.8% on time, 24 points below January, the best at 88.5%. 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. July was the busiest month here, with 188 flights.
Across the week, Saturday is the strongest day at 87.4% on time and Monday the weakest at 72.2%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 23,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 49%Late-arriving aircraft
- 32%Carrier
- 16%National Airspace System
- 3%Extreme weather
49% 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 23,000 reported delay minutes here, that single category outweighs weather by 18 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 22,755 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.0% on time here.
Cancellations run at 2.75%, against 1.81% nationally. That is roughly one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
7.1% 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 about an hour, which a normal layover absorbs.
The 611 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 75.7% on time across 1,844 flights, 3 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 3 points of difference.
The sample behind these figures is 1,852 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 BWI 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 88.5% on time and July 64.8%, a swing of 24 points. If the dates move at all, move them out of July before you think about anything else. 1,796 completed flights over 12 months sit behind that.
Common questions
MDW to BWI questions
How often is MDW to BWI delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.1% of the 1,852 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is MDW to BWI compared with the rest of the country?
78.9% of flights arrive on time here against a national 77.6%, a difference of about a point in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on MDW to BWI?
The 5am–8am departure window is the strongest at 93.0% on time. The 5pm–8pm window is the weakest at 61.9%, 31 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 MDW to BWI?
July is the weakest month at 64.8% on time, compared with 88.5% in January. Across the year that is 24 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
- BWI to MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- MDW to ATL, a related route79.8%
- ATL to BWI, a related route75.6%
- MDW to PHX, a related route75.0%
- Frontier Airlines on-time record79.5%
- Southwest Airlines on-time record78.9%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. MDW to BWI and BWI to MDW 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.