Flight number record
OO 4636
SkyWest Airlines · Chicago to South Bend
- Route
- ORD → SBN
- Departs
- 17:50
- Flights
- 330
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s OO 4636, 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 4636 earns an F−, which is as low as this site's scale goes for a reason. Only 51.5% of flights arrive inside the 15-minute window, 26 points worse than the national rate of 77.6%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 330 flights, with a median arrival 12 minutes late.
The national on-time rate over the same period is 77.6%, so OO 4636 runs 26 points behind the country as a whole. Across a thousand flights that is about 261 extra late arrivals.
Key figures
On time
51.5%
Arrivals under 15 minutes late, of 309 completed flights
Avg delay
89 min
Across delayed arrivals only, not all flights
Cancelled
6.36%
National rate is 1.81%
1 hour+ late
21.7%
National rate is 8.1%
These figures cover 330 flights between July 2025 and June 2026. Beyond the headline rate, 21.7% 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.
Schedule
When OO 4636 flies
OO 4636 flies ORD to SBN without a single fixed slot. Its most common scheduled departure was 17:50, used on 131 of 330 flights, with 17:55 (56 flights) and 17:45 (45 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 17:50131 flights39.7%
- Departs 17:5556 flights17.0%
- Departs 17:4545 flights13.6%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and OO 4636 runs 17 points worse at 51.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
OO 4636 next to ORD to SBN
Every carrier on ORD to SBN combined arrived on time 62.7% of the time across 2,704 flights, so OO 4636 is 11 points behind it. SkyWest flew 2,692 flights on the same city pair under all its flight numbers, including this one, and those ran 62.5% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight trails by 28 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4636thin sample | 330 | 51.5% | 89 min | 6.36% | F− |
| All SkyWest Airlines on ORD–SBN | 2,692 | 62.5% | 87 min | 4.27% | D− |
| All carriers on ORD–SBN | 2,704 | 62.7% | 87 min | 4.25% | D− |
| SkyWest Airlines, whole network | 852,935 | 79.0% | 88 min | 1.77% | B |
Across the year
OO 4636 quarter by quarter
OO 4636 did not run the same all year. Its best quarter was Jul–Sep 2025 at 57.8% on time and its weakest Jan–Mar 2026 at 46.3%, a swing of 12 points on roughly 83 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 202586 flights57.8%
- Oct–Dec 202563 flights49.2%
- Jan–Mar 202690 flights46.3%
- Apr–Jun 202691 flights51.8%
Scale runs 40% to 65%. Rows with fewer than 30 flights show a dash.
By weekday, OO 4636 did best on Monday at 61.4% on time and worst on Saturday at 38.1%. Each day rests on about 47 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Delay causes
Why OO 4636 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 13,000 reported delay minutes.
- 42%Carrier
- 30%Late-arriving aircraft
- 24%National Airspace System
- 4%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 5,595 of the 13,000 delay minutes reported here. The split is drawn from 13,389 delay minutes reported on OO 4636.
Cancellations run at 6.36%, against 1.81% nationally. That is about one flight in fifteen 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 21.7% 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 same number turns up on two other city pairs in the data, including ORD to ABE (31) and OMA to ORD (1), but none flew often enough under OO 4636 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to SBN only.
One caution: this is a thin sample. 330 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 4636
For a booking, the cancellation rate is the figure to plan around on OO 4636: 6.36% of its 330 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ORD to SBN, every carrier and departure
- SBN to ORD, the return direction
- SkyWest Airlines 4791 on the same route67.8%
- SkyWest Airlines 5499 on the same route55.5%
- SkyWest Airlines 5274 on the same route69.3%
- SkyWest Airlines 5505 on the same route61.2%
- 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
- How often a connection fails at the major US hubs
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.