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DelayAtlas

Carrier route record

UACHSORD

United Airlines · Charleston to Chicago

Flights
749
Period
July 2025 to June 2026
Share of route
36%
Carriers
6
BGRADE

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on CHS to ORD lands a B, level with the national rate of 77.6%. Roughly one flight in four arrives 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 749 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 562 at 80.1% on time.

The US average over the same twelve months is 77.6%, so there is little to separate United on CHS to ORD from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

77.1%

Arrivals under 15 minutes late, of 729 completed flights

Avg delay

73 min

Across delayed arrivals only, not all flights

Cancelled

2.00%

National rate is 1.81%

Whole route

76.6%

Every carrier on CHS to ORD, 2,091 flights

These figures cover 749 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

United against every carrier on CHS to ORD

United flew 749 of the 2,091 flights on CHS to ORD, about 36% of it. Its 77.1% on time is about level with the route as a whole at 76.6%. Ranked by on-time rate it is number four of six carriers on the route, where the range runs from PSA at 100.0% to SkyWest at 69.1%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Envoy Air arrives on time 80.1% of the time; Republic Airways manages 70.5%. Sample sizes sit next to every figure, because a two-point gap across 456 flights means less than a ten-point one.

On-time performance by carrier on CHS to ORD
AirlineFlightsOn timeAvg delayCancelledGrade
PSA Airlinesthin sample1100.0%0.00%A+
American Airlinesthin sample23881.0%118 min1.68%B
Envoy Air56280.1%75 min2.67%B
United Airlines (this page)74977.1%73 min2.00%B
Republic Airways45670.5%52 min3.07%C−
SkyWest Airlinesthin sample8569.1%124 min4.71%C−

Republic Airways cancels 3.1% 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

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 39 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am237 flights85.4%
  • 8am–11am103 flights81.6%
  • 11am–2pm232 flights86.8%
  • 2pm–5pm83 flights52.5%
  • 5pm–8pm92 flights48.3%
  • 8pm–5am2 flights

Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 48.3% on time, against 86.8% for the 11am–2pm 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 237 flights scheduled in it.

Across the year

United on CHS to ORD through the year

On-time rate by calendar month69J68F62M63A78M85J84J93A86S88O77N74D
Darker means more delays. Figures are on-time percentages.August best, March worst

Delays peak in March, when the on-time rate falls to 62.3%. August is the strongest month at 92.5%. Moving a flexible trip across that boundary buys 30 points. November was the busiest month here, with 90 flights.

Across the week, Thursday is the strongest day at 83.3% on time and Sunday the weakest at 71.7%. 12 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week76.7Mon78.6Tue74.0Wed83.3Thu75.0Fri80.9Sat71.7Sun
Monday: 76.7 percent on time. Tuesday: 78.6 percent on time. Wednesday: 74.0 percent on time. Thursday: 83.3 percent on time. Friday: 75.0 percent on time. Saturday: 80.9 percent on time. Sunday: 71.7 percent on time

Delay causes

Why United runs late on this route

One category carries most of the weight here. National Airspace System accounts for 51% of the 12,000 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.

  • National Airspace System
    51%
  • Carrier
    26%
  • Late-arriving aircraft
    20%
  • Extreme weather
    3%

51% 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 6,146 minutes out of 12,000, against a national NAS share of 21%. The split is drawn from 12,120 reported delay minutes.

Cancellations sit at 2.00% against a national 1.81%, which is ordinary. Diversions add another 0.67%.

Connections and stage length

What a delay here costs

7.7% 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 a little over an hour, which a normal layover absorbs.

The 760 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 74.2% on time across 750 flights, within 3 points 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. 749 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.

What to do with this

Booking United on CHS to ORD

Put together: treat all of this as provisional. 749 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 77.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 729 completed flights over 12 months sit behind that.

Related

Where to go next

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.