Route reliability record
RDU→MDW
Raleigh to Chicago
- Flights
- 988
- Period
- July 2025 to June 2026
- Distance
- 632 mi
- Carriers
- 1
This route lands a B, 2 points 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 55 minutes on average. That is a workable record, not a spotless one. That rests on 988 RDU to MDW flights, with a median arrival 5 minutes early.
Best time to fly RDU to MDW: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 95.6% of the time and Tuesday flights 83.9%, against 79.3% 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
79.3%
Arrivals under 15 minutes late, of 962 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
2.02%
National rate is 1.81%
Best carrier
Southwest
79.3% on time across 988 flights
These figures cover 988 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 RDU to MDW
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 988 | 79.3% | 54 min | 2.02% | B |
Best ways to make this trip
The most reliable ways to fly Raleigh to Chicago
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. RDU → ORDRaleigh to Chicago | American Airlines | 79.4% | 82.2% | 3.44% | 8am–11am, Fri | — |
| 2. RDU → MDWRaleigh to Chicago | Southwest Airlines | 77.7% | 79.3% | 2.02% | 5am–8am, Tue | — |
| 3. RDU → ORDRaleigh to Chicago | United Airlines | 75.4% | 76.3% | 1.16% | 5am–8am, Tue | UA 1920 13:30 |
| 4. RDU → ORDRaleigh to Chicago | Envoy Air | 71.1% | 72.3% | 1.72% | 5am–8am, Wed | — |
| 5. RDU → ORDRaleigh to Chicago | Republic Airways | 68.1% | 70.7% | 3.63% | 8am–11am, Sat | — |
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 36 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–8am258 flights95.6%
- 8am–11am109 flights84.9%
- 11am–2pm195 flights82.2%
- 2pm–5pm72 flights66.2%
- 5pm–8pm297 flights68.1%
- 8pm–5am57 flights59.3%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.3% on time, against 95.6% 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 5pm–8pm window is the busiest, with 297 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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.
November is the best month on the calendar at 93.9% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 119 flights.
Across the week, Tuesday is the strongest day at 83.9% on time and Monday the weakest at 77.1%. 7 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 56% of the 11,000 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.
- 56%Late-arriving aircraft
- 22%Carrier
- 18%National Airspace System
- 4%Extreme weather
- 0%Security
56% 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 11,000 reported delay minutes here, that single category outweighs weather by 16 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 10,780 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 95.6% on time here.
Cancellations sit at 2.02% against a national 1.81%, which is ordinary. Diversions add another 0.61%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 632 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 runs 80.7% on time across 987 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 988 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in MDW after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 988 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 79.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 962 completed flights over 12 months sit behind that.
Common questions
RDU to MDW questions
How often is RDU to MDW 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 20.7% of the 988 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 55 minutes on average.
How reliable is RDU to MDW compared with the rest of the country?
79.3% of flights arrive on time here against a national 77.6%, a difference of 2 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on RDU to MDW?
The 5am–8am departure window is the strongest at 95.6% on time. The 8pm–5am window is the weakest at 59.3%, 36 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 March delays on RDU to MDW?
March is the weakest month at 66.7% on time, compared with 93.9% in November. Across the year that is 27 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
- MDW to RDU — the return legseparate record
- Raleigh-Durham International (RDU) delay statistics
- Chicago Midway International (MDW) delay statistics
- RDU to ATL, a related route87.6%
- ATL to MDW, a related route76.3%
- RDU to ORD, a related route74.4%
- Southwest Airlines on-time record79.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. RDU to MDW and MDW to RDU 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.