Flight number record
OO 5140
SkyWest Airlines · Chicago to Hancock
- Route
- ORD → CMX
- Departs
- 21:25
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 5140, check with SkyWest Airlines. SkyWest Airlines flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
OO 5140 draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about 2.7 hours behind schedule. Build slack into anything you connect to. That rests on 364 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.3%, so OO 5140 runs 14 points behind the country as a whole. Across a thousand flights that is about 143 extra late arrivals.
Key figures
On time
63.0%
Arrivals under 15 minutes late, of 327 completed flights
Avg delay
162 min
Across delayed arrivals only, not all flights
Cancelled
7.97%
National rate is 1.89%
1 hour+ late
16.8%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 16.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When OO 5140 flies
OO 5140 flies ORD to CMX without a single fixed slot. Its most common scheduled departure was 21:25, used on 97 of 364 flights, with 21:39 (56 flights) and 21:18 (52 flights) next.
- Departs 21:2597 flights26.6%
- Departs 21:3956 flights15.4%
- Departs 21:1852 flights14.3%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 21:25 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and OO 5140 runs 7 points worse at 63.0%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
OO 5140 next to ORD to CMX
Every carrier on ORD to CMX combined arrived on time 67.6% of the time across 788 flights, so OO 5140 is 5 points behind it. Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 16 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 5140thin sample | 364 | 63.0% | 162 min | 7.97% | D− |
| All SkyWest Airlines on ORD–CMX | 788 | 67.6% | 129 min | 7.11% | C− |
| All carriers on ORD–CMX | 788 | 67.6% | 129 min | 7.11% | C− |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 5140 quarter by quarter
OO 5140 did not run the same all year. Its best quarter was Oct–Dec 2025 at 68.6% on time and its weakest Jan–Mar 2026 at 54.3%, a swing of 14 points on roughly 91 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights—
- Oct–Dec 202591 flights68.6%
- Jan–Mar 202690 flights54.3%
- Apr–Jun 202691 flights64.6%
- Jul–Sep 202662 flights54.5%
Scale runs 45% to 75%. Rows with fewer than 30 flights show a dash.
By weekday, OO 5140 did best on Monday at 76.1% on time and worst on Sunday at 50.0%. Each day rests on about 52 flights, so a gap of 26 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 5140 runs when it is late
The 121 late arrivals split 37 under half an hour, 29 between 30 and 60 minutes, and 55 an hour or more.
- 15+ min early65 flights19.9%
- Within 15 min141 flights43.1%
- 15–29 min late37 flights11.3%
- 30–59 min late29 flights8.9%
- 1–2 hours late25 flights7.6%
- 2+ hours late30 flights9.2%
Scale runs 0% to 100%.
Share of 327 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 92 departures that left 15 minutes late or more, only 4 made it up before arrival. In the other direction, 33 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at CMX.
The worst days
Worst days for OO 5140
The latest arrival of the period was on 13 April 2026, 15 hours 53 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across April, February, December and June, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 April 2026 | 15 hours 53 minutes | National Airspace System |
| 24 February 2026 | 15 hours 44 minutes | Carrier |
| 15 February 2026 | 13 hours 46 minutes | Extreme weather |
| 31 December 2025 | 13 hours 43 minutes | Late-arriving aircraft |
| 9 June 2026 | 13 hours 31 minutes | Extreme weather |
Delay causes
Why OO 5140 runs late
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 20,000 reported delay minutes.
- 35%Carrier
- 30%Late-arriving aircraft
- 22%Extreme weather
- 14%National Airspace System
Extreme weather accounts for 22% 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 quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.7 times the usual weather exposure. The split is drawn from 19,618 delay minutes reported on OO 5140.
Cancellations run at 7.97%, against 1.89% nationally. That is about one flight in twelve 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 routes
What a delay on this flight costs
16.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The same number turns up on one other city pair in the data, including GRB to CMX (1), but none flew often enough under OO 5140 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to CMX only.
One caution: this is a thin sample. 364 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 OO 5140
For a booking, the cancellation rate is the figure to plan around on OO 5140: 7.97% of its 364 scheduled flights did not operate. A late arrival costs about 2.7 hours, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ORD to CMX, every carrier and departure
- CMX to ORD, the return direction
- Chicago O'Hare International (ORD) delay statistics
- SkyWest Airlines on-time record
- Every SkyWest Airlines flight number with a record
- The most and least reliable flight numbers in the US
- What a cancellation rate actually tells you (and what it hides)
A flight number here means SkyWest Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.