Flight number record
OO 4308
SkyWest Airlines · Salt Lake City to St. George
- Route
- SLC → SGU
- Departs
- 09:30
- Flights
- 311
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4308, 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 4308 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 17 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 40 minutes. That rests on 311 flights, with a median arrival 14 minutes early.
Set against the rest of the country, OO 4308's record is 17 points better than the US average of 77.3%. That gap is worth roughly 169 fewer late arrivals for every thousand flights.
Key figures
On time
94.2%
Arrivals under 15 minutes late, of 308 completed flights
Avg delay
41 min
Across delayed arrivals only, not all flights
Cancelled
0.64%
National rate is 1.89%
1 hour+ late
1.3%
National rate is 8.3%
These figures cover 311 flights between September 2025 and August 2026. The median arrival is 14 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 4308 flies
OO 4308 is scheduled to leave Salt Lake City (SLC) at 09:30 local time and reach St. George (SGU) at 10:45. That slot held for 294 of the 311 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.
- Departs 09:30294 flights94.5%
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 4308 runs 10 points better at 94.2%. 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 4308 next to SLC to SGU
Every carrier on SLC to SGU combined arrived on time 91.4% of the time across 1,727 flights, so OO 4308 is 3 points ahead of it. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 16 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4308thin sample | 311 | 94.2% | 41 min | 0.64% | A+ |
| All SkyWest Airlines on SLC–SGU | 1,727 | 91.4% | 81 min | 0.17% | A+ |
| All carriers on SLC–SGU | 1,727 | 91.4% | 81 min | 0.17% | A+ |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4308 quarter by quarter
Quarter by quarter OO 4308 held fairly steady: 93.7% in Oct–Dec 2025, 91.8% in Jan–Mar 2026, 98.7% in Apr–Jun 2026 and 93.0% in Jul–Sep 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202525 flights—
- Oct–Dec 202581 flights93.7%
- Jan–Mar 202685 flights91.8%
- Apr–Jun 202677 flights98.7%
- Jul–Sep 202643 flights93.0%
Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, OO 4308 ranged from 92.2% on Friday to 98.0% on Wednesday. With about 44 flights behind each day, a spread of 6 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late OO 4308 runs when it is late
OO 4308 often beats the schedule: 144 of 308 completed flights, 47%, arrived 15 minutes or more early. Most of the lateness is short. 9 of the 18 late arrivals were under half an hour behind, and 4 reached an hour or more.
- 15+ min early144 flights46.8%
- Within 15 min146 flights47.4%
- 15–29 min late9 flights2.9%
- 30–59 min late5 flights1.6%
- 1–2 hours late3 flights1.0%
- 2+ hours late1 flights0.3%
Scale runs 0% to 100%.
Share of 308 completed flights by arrival against schedule.
Only 16 of 308 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for OO 4308
The latest arrival of the period was on 29 October 2025, 2 hours 22 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 October 2025 | 2 hours 22 minutes | Carrier |
| 28 August 2026 | 1 hour 16 minutes | Extreme weather |
| 8 September 2025 | 1 hour 4 minutes | Carrier |
| 2 January 2026 | 1 hour | Carrier |
| 17 February 2026 | 57 minutes | Carrier |
Delay causes
Why OO 4308 runs late
Carrier accounts for 73% of the 737 delay minutes carriers reported here, and the remaining four split what is left.
- 73%Carrier
- 24%Extreme weather
- 3%National Airspace System
Extreme weather accounts for 24% 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 4.0 times the usual weather exposure. The split is drawn from 737 delay minutes reported on OO 4308.
Cancellations are rare at 0.64%, 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
Badly late arrivals are rare here: only 1.3% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
OO 4308 is not only a SLC to SGU flight. It also flew SGU to SLC (311 flights, 93.9% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 311 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SGU to SLCthin sample | 311 | 93.9% | 52 min | 0.64% | A+ |
What to do with this
Booking OO 4308
For a booking, OO 4308 has one of the better records a US domestic flight can show: 94.2% on time and 0.64% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- SLC to SGU, every carrier and departure
- SGU to SLC, the return direction
- SkyWest Airlines 4279 on the same route92.2%
- SkyWest Airlines 4321 on the same route92.1%
- SkyWest Airlines 4253 on the same route93.6%
- SkyWest Airlines 4263 on the same route84.0%
- Salt Lake City International (SLC) 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 to read this site: grades, sample sizes, and honest caveats
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.