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DelayAtlas

Route reliability record

RSWORD

Fort Myers to Chicago

Flights
3,232
Period
July 2025 to June 2026
Distance
1,120 mi
Carriers
5
BGRADE

This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four 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 3,232 flights, of which United Airlines flew 1,612 at 80.7% on time.

United Airlines is the most reliable of the three carriers covered here at 80.7% on time across 1,612 flights.

Key figures

On time

76.5%

Arrivals under 15 minutes late, of 3,152 completed flights

Avg delay

81 min

Across delayed arrivals only, not all flights

Cancelled

1.70%

National rate is 1.81%

Best carrier

United

80.7% on time across 1,612 flights

These figures cover 3,232 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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 RSW to ORD

The choice of carrier is not cosmetic here. United Airlines arrives on time 80.7% of the time; Spirit Airlines manages 70.1%. Sample sizes sit next to every figure, because a two-point gap across 365 flights means less than a ten-point one.

On-time performance by carrier on RSW to ORD
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines1,61280.7%73 min0.68%B+
American Airlines1,11674.3%91 min1.97%C
Frontier Airlinesthin sample3671.4%97 min2.78%C
Spirit Airlines36570.1%77 min5.21%C−
Southwest Airlinesthin sample10356.0%78 min1.94%D

Spirit Airlines cancels 5.2% 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 40 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am481 flights89.3%
  • 8am–11am507 flights91.1%
  • 11am–2pm880 flights81.8%
  • 2pm–5pm820 flights66.3%
  • 5pm–8pm423 flights59.6%
  • 8pm–5am121 flights50.9%

Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 50.9% on time, against 91.1% 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. The 11am–2pm window is the busiest, with 880 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 23 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 month74J74F73M79A80M78J69J81A92S84O75N72D
Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 68.8% on time, 23 points below September, the best at 91.6%. 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. March was the busiest month here, with 468 flights.

Across the week, Thursday is the strongest day at 80.7% on time and Sunday the weakest at 70.9%. 10 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week73.5Mon80.5Tue78.7Wed80.7Thu75.8Fri75.9Sat70.9Sun
Monday: 73.5 percent on time. Tuesday: 80.5 percent on time. Wednesday: 78.7 percent on time. Thursday: 80.7 percent on time. Friday: 75.8 percent on time. Saturday: 75.9 percent on time. Sunday: 70.9 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 60,000 reported delay minutes.

  • National Airspace System
    41%
  • Late-arriving aircraft
    34%
  • Carrier
    19%
  • Extreme weather
    6%

41% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 25,000 minutes out of 60,000, against a national NAS share of 21%. The split is drawn from 60,068 reported delay minutes.

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 91.1% on time here.

Cancellations sit at 1.70% against a national 1.81%, which is ordinary. Diversions add another 0.77%.

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. 9.3% of arrivals land a full hour or more behind schedule, against 8.1% 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.

The 1,120 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 76.1% on time across 3,239 flights, within half 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 3,232 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 91.6% on time and July 68.8%, a swing of 23 points. If the dates move at all, move them out of July before you think about anything else. 3,152 completed flights over 12 months sit behind that.

Common questions

RSW to ORD questions

How often is RSW to ORD delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.5% of the 3,232 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on RSW to ORD?

United Airlines leads at 80.7% on time across 1,612 flights. Spirit Airlines is at the other end on 70.1%, a gap of 11 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 RSW to ORD?

The 8am–11am departure window is the strongest at 91.1% on time. The 8pm–5am window is the weakest at 50.9%, 40 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 RSW to ORD?

July is the weakest month at 68.8% on time, compared with 91.6% in September. Across the year that is 23 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, July 2025 to June 2026. Updated monthly. How this data is collected.