Flight number record

OO 4230

SkyWest Airlines · Grand Junction to Salt Lake City

Route: GJT → SLC
Departs: 07:40
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 4230, 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 4230 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 20 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 2.5 hours. That rests on 365 flights, with a median arrival 18 minutes early.

Set against the rest of the country, OO 4230's record is 20 points better than the US average of 77.6%. That gap is worth roughly 197 fewer late arrivals for every thousand flights.

On time

97.3%

Arrivals under 15 minutes late, of 365 completed flights

Avg delay

152 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

1 hour+ late

1.6%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 18 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.

Schedule

When OO 4230 flies

OO 4230 flies GJT to SLC without a single fixed slot. Its most common scheduled departure was 07:40, used on 120 of 365 flights, with 06:00 (69 flights) and 07:45 (60 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:40120 flights32.9%
Departs 06:0069 flights18.9%
Departs 07:4560 flights16.4%

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 07:40 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and OO 4230 runs 8 points better at 97.3%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

OO 4230 next to GJT to SLC

Every carrier on GJT to SLC combined arrived on time 94.2% of the time across 582 flights, so OO 4230 is 3 points ahead of it. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 18 points.

OO 4230 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 4230	365	97.3%	152 min	0.00%	A+
All SkyWest Airlines on GJT–SLC	582	94.2%	76 min	0.00%	A+
All carriers on GJT–SLC	582	94.2%	76 min	0.00%	A+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 4230 quarter by quarter

Quarter by quarter OO 4230 held fairly steady: 97.8% in Jul–Sep 2025, 97.8% in Oct–Dec 2025, 97.8% in Jan–Mar 2026 and 95.6% in Apr–Jun 2026. A spread of 2 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights97.8%
Oct–Dec 202592 flights97.8%
Jan–Mar 202690 flights97.8%
Apr–Jun 202691 flights95.6%

Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, OO 4230 ranged from 92.3% on Friday to 100.0% on Thursday. With about 52 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why OO 4230 runs late

One category carries most of the weight here. Carrier accounts for 95% of the 1,518 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
95%
National Airspace System
4%
Extreme weather
1%

The largest share of delay minutes, 95%, 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 1,446 of the 1,518 delay minutes reported here. The split is drawn from 1,518 delay minutes reported on OO 4230.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are 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 1.6% land an hour or more behind schedule, against 8.1% 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.

Every one of the 365 flights under OO 4230 in the data flew GJT to SLC. 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. 365 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 4230

For a booking, OO 4230 has one of the better records a US domestic flight can show: 97.3% on time and 0.00% cancelled. That is a base rate, not a promise about any single day.

Where to go next

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.

Key figures