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DelayAtlas

Route reliability record

ORDBNA

Chicago to Nashville

Flights
5,031
Period
June 2025 to May 2026
Distance
409 mi
Carriers
9
CGRADE

This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.4%. The late ones land a little over an hour behind schedule. That rests on 5,031 flights, of which Republic Airways flew 569 at 75.7% on time.

Republic Airways is the most reliable of the six carriers covered here at 75.7% on time across 569 flights.

Key figures

On time

68.7%

Arrivals under 15 minutes late, of 4,901 completed flights

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

2.37%

National rate is 1.80%

Best carrier

Republic

75.7% on time across 569 flights

These figures cover 5,031 flights between June 2025 and May 2026. Beyond the headline rate, 13.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airline is most reliable on ORD to BNA

The choice of carrier is not cosmetic here. Republic Airways arrives on time 75.7% of the time; SkyWest Airlines manages 61.4%. Sample sizes sit next to every figure, because a two-point gap across 1,444 flights means less than a ten-point one.

On-time performance by carrier on ORD to BNA
AirlineFlightsOn timeAvg delayCancelledGrade
PSA Airlinesthin sample3100.0%0.00%A+
Republic Airways56975.7%55 min1.41%B
Envoy Air74974.1%61 min3.34%C−
United Airlines1,34672.3%70 min1.56%C
Southwest Airlines36569.3%58 min1.10%C
Frontier Airlinesthin sample9668.8%76 min3.12%C−
Spirit Airlinesthin sample3565.7%178 min0.00%C+
American Airlines42462.6%123 min2.12%D
SkyWest Airlines1,44461.4%88 min3.39%D−

SkyWest Airlines cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

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 26 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am562 flights83.1%
  • 8am–11am679 flights77.9%
  • 11am–2pm1,085 flights72.2%
  • 2pm–5pm1,023 flights68.3%
  • 5pm–8pm758 flights57.3%
  • 8pm–5am924 flights58.2%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 57.3% on time, against 83.1% 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.

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.

On-time rate by calendar month68J72F61M74A75M68J56J75A80S67O69N57D
Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 56.2% on time, 24 points below September, the best at 79.8%. 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, Saturday is the strongest day at 74.7% on time and Monday the weakest at 64.3%. 10 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week64.3Mon71.3Tue70.6Wed70.6Thu65.6Fri74.7Sat65.6Sun
Monday: 64.3 percent on time. Tuesday: 71.3 percent on time. Wednesday: 70.6 percent on time. Thursday: 70.6 percent on time. Friday: 65.6 percent on time. Saturday: 74.7 percent on time. Sunday: 65.6 percent on time

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 121,000 reported delay minutes.

  • Late-arriving aircraft
    39%
  • Carrier
    29%
  • National Airspace System
    20%
  • Extreme weather
    12%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure.

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 121,000 reported delay minutes here, that single category outweighs weather by 3 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.

Cancellations sit at 2.37% against a national 1.80%, which is ordinary. Diversions add another 0.22%.

Connections and stage length

What a delay here actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 13.1% of arrivals land a full hour or more behind schedule, against 8.2% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 409 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 runs 70.0% on time across 5,034 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.

The sample behind these figures is 5,031 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. September runs 79.8% on time and July 56.2%, a swing of 24 points. If the dates move at all, move them out of July before you think about anything else.

Common questions

ORD to BNA questions

How often is ORD to BNA delayed?

About one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 31.3% of the 5,031 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 ORD to BNA?

Republic Airways leads at 75.7% on time across 569 flights. SkyWest Airlines is at the other end on 61.4%, a gap of 14 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 ORD to BNA?

The 5am–8am departure window is the strongest at 83.1% on time. The 5pm–8pm window is the weakest at 57.3%, 26 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 ORD to BNA?

July is the weakest month at 56.2% on time, compared with 79.8% in September. 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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.