Flight number record
OO 5634
SkyWest Airlines · Colorado Springs to Denver
- Route
- COS → DEN
- Departs
- 09:30
- Flights
- 348
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 5634, 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 5634 earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 348 flights, with a median arrival 5 minutes early.
Set against the rest of the country, OO 5634's record is 8 points better than the US average of 77.3%. That gap is worth roughly 77 fewer late arrivals for every thousand flights.
Key figures
On time
85.0%
Arrivals under 15 minutes late, of 347 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
0.29%
National rate is 1.89%
1 hour+ late
5.2%
National rate is 8.3%
These figures cover 348 flights between September 2025 and August 2026. The median arrival is 5 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When OO 5634 flies
OO 5634 flies COS to DEN without a single fixed slot. Its most common scheduled departure was 09:30, used on 144 of 348 flights, with 09:20 (82 flights) and 09:23 (40 flights) next.
- Departs 09:30144 flights41.4%
- Departs 09:2082 flights23.6%
- Departs 09:2340 flights11.5%
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 09:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and OO 5634 runs level with that at 85.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
OO 5634 next to COS to DEN
Every carrier on COS to DEN combined arrived on time 81.4% of the time across 4,989 flights, so OO 5634 is 4 points ahead of it. SkyWest flew 3,337 flights on the same city pair under all its flight numbers, including this one, and those ran 83.4% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 5634thin sample | 348 | 85.0% | 76 min | 0.29% | A+ |
| All SkyWest Airlines on COS–DEN | 3,337 | 83.4% | 77 min | 1.53% | B |
| All carriers on COS–DEN | 4,989 | 81.4% | 72 min | 1.14% | B |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 5634 quarter by quarter
OO 5634 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jan–Mar 2026 at 82.2%, a swing of 11 points on roughly 70 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 flights93.3%
- Oct–Dec 202575 flights82.7%
- Jan–Mar 202690 flights82.2%
- Apr–Jun 202691 flights85.6%
- Jul–Sep 202662 flights87.1%
Scale runs 75% to 100%.
By weekday, OO 5634 did best on Wednesday at 95.8% on time and worst on Thursday at 73.5%. Each day rests on about 50 flights, so a gap of 22 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 5634 runs when it is late
The 52 late arrivals split 17 under half an hour, 17 between 30 and 60 minutes, and 18 an hour or more.
- 15+ min early86 flights24.8%
- Within 15 min209 flights60.2%
- 15–29 min late17 flights4.9%
- 30–59 min late17 flights4.9%
- 1–2 hours late8 flights2.3%
- 2+ hours late10 flights2.9%
Scale runs 0% to 100%.
Share of 347 completed flights by arrival against schedule.
15 of 54 late departures made up the time and arrived on time, 28% of them. 13 flights left on time and still arrived late.
The worst days
Worst days for OO 5634
The latest arrival of the period was on 24 January 2026, 6 hours 6 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 January 2026 | 6 hours 6 minutes | Carrier |
| 17 February 2026 | 6 hours 6 minutes | Carrier |
| 6 March 2026 | 5 hours 49 minutes | Extreme weather |
| 31 January 2026 | 3 hours 41 minutes | Extreme weather |
| 11 January 2026 | 3 hours | Carrier |
Delay causes
Why OO 5634 runs late
Carrier accounts for 55% of the 3,972 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Carrier
- 21%Extreme weather
- 16%Late-arriving aircraft
- 8%National Airspace System
Extreme weather accounts for 21% 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 3.5 times the usual weather exposure. The split is drawn from 3,972 delay minutes reported on OO 5634.
Cancellations are rare at 0.29%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
5.2% 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 a little over an hour, which a normal layover absorbs.
Every one of the 348 flights under OO 5634 in the data flew COS to DEN. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 348 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 5634
For a booking, OO 5634 has one of the better records a US domestic flight can show: 85.0% on time and 0.29% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- COS to DEN, every carrier and departure
- DEN to COS, the return direction
- SkyWest Airlines 4675 on the same route83.5%
- SkyWest Airlines 4696 on the same route89.7%
- SkyWest Airlines 5291 on the same route90.6%
- SkyWest Airlines 4719 on the same route67.7%
- 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.