Flight number record
OO 5857
SkyWest Airlines · Columbia to Denver
- Route
- COU → DEN
- Departs
- 09:00
- Flights
- 310
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 5857, 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 5857 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 310 flights, with a median arrival 9 minutes early.
Set against the rest of the country, OO 5857's record is 11 points better than the US average of 77.3%. That gap is worth roughly 112 fewer late arrivals for every thousand flights.
Key figures
On time
88.5%
Arrivals under 15 minutes late, of 305 completed flights
Avg delay
95 min
Across delayed arrivals only, not all flights
Cancelled
1.29%
National rate is 1.89%
1 hour+ late
5.6%
National rate is 8.3%
These figures cover 310 flights between September 2025 and August 2026. The median arrival is 9 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.
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Schedule
When OO 5857 flies
OO 5857 flies COU to DEN without a single fixed slot. Its most common scheduled departure was 09:00, used on 116 of 310 flights, with 09:14 (82 flights) and 08:45 (56 flights) next.
- Departs 09:00116 flights37.4%
- Departs 09:1482 flights26.5%
- Departs 08:4556 flights18.1%
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 09:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and OO 5857 runs 5 points better at 88.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
OO 5857 next to COU to DEN
Every carrier on COU to DEN combined arrived on time 88.1% of the time across 340 flights, so OO 5857 is about level with it. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 5857thin sample | 310 | 88.5% | 95 min | 1.29% | A |
| All SkyWest Airlines on COU–DENthin sample | 340 | 88.1% | 88 min | 1.18% | A |
| All carriers on COU–DENthin sample | 340 | 88.1% | 88 min | 1.18% | A |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 5857 quarter by quarter
OO 5857 did not run the same all year. Its best quarter was Apr–Jun 2026 at 95.6% on time and its weakest Oct–Dec 2025 at 80.3%, a swing of 15 points on roughly 78 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.
- Oct–Dec 202567 flights80.3%
- Jan–Mar 202690 flights89.7%
- Apr–Jun 202691 flights95.6%
- Jul–Sep 202662 flights85.5%
Scale runs 70% to 100%.
By weekday, OO 5857 ranged from 83.7% on Saturday to 95.5% on Wednesday. With about 44 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late OO 5857 runs when it is late
OO 5857 often beats the schedule: 100 of 305 completed flights, 33%, arrived 15 minutes or more early. The 35 late arrivals split 7 under half an hour, 11 between 30 and 60 minutes, and 17 an hour or more.
- 15+ min early100 flights32.8%
- Within 15 min170 flights55.7%
- 15–29 min late7 flights2.3%
- 30–59 min late11 flights3.6%
- 1–2 hours late6 flights2.0%
- 2+ hours late11 flights3.6%
Scale runs 0% to 100%.
Share of 305 completed flights by arrival against schedule.
7 of 30 late departures made up the time and arrived on time, 23% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for OO 5857
The latest arrival of the period was on 27 April 2026, 5 hours 28 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 27 April 2026 | 5 hours 28 minutes | Carrier |
| 11 December 2025 | 5 hours 15 minutes | National Airspace System |
| 15 August 2026 | 4 hours 9 minutes | Carrier |
| 24 January 2026 | 4 hours 8 minutes | Extreme weather |
| 6 August 2026 | 3 hours 56 minutes | Carrier |
Delay causes
Why OO 5857 runs late
Carrier accounts for 60% of the 3,331 delay minutes carriers reported here, and the remaining four split what is left.
- 60%Carrier
- 24%National Airspace System
- 11%Late-arriving aircraft
- 5%Extreme weather
The largest share of delay minutes, 60%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,998 of the 3,331 delay minutes reported here. The split is drawn from 3,331 delay minutes reported on OO 5857.
Cancellations sit at 1.29% against a national 1.89%, which is ordinary. Diversions add another 0.32%.
Connections and routes
What a delay on this flight costs
5.6% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 671 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.
The same number turns up on one other city pair in the data, including ORD to MSN (3), but none flew often enough under OO 5857 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to COU to DEN only.
One caution: this is a thin sample. 310 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 5857
For a booking, OO 5857 has one of the better records a US domestic flight can show: 88.5% on time and 1.29% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- Denver International (DEN) 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
- Worst months to fly in the US, ranked by the data
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.