Flight number record

OO 3859

SkyWest Airlines · Great Falls to Salt Lake City

Route: GTF → SLC
Departs: 11:43
Flights: 364
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 3859, 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 3859 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 15 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 364 flights, with a median arrival 14 minutes early.

Set against the rest of the country, OO 3859's record is 15 points better than the US average of 77.6%. That gap is worth roughly 149 fewer late arrivals for every thousand flights.

On time

92.5%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

51 min

Across delayed arrivals only, not all flights

Cancelled

1.37%

National rate is 1.81%

1 hour+ late

1.9%

National rate is 8.1%

These figures cover 364 flights between July 2025 and June 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.

Schedule

When OO 3859 flies

OO 3859 flies GTF to SLC without a single fixed slot. Its most common scheduled departure was 11:43, used on 66 of 364 flights, with 13:12 (63 flights) and 13:05 (61 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:4366 flights18.1%
Departs 13:1263 flights17.3%
Departs 13:0561 flights16.8%

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 11:43 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and OO 3859 runs 14 points better at 92.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

OO 3859 next to GTF to SLC

Every carrier on GTF to SLC combined arrived on time 92.3% of the time across 1,071 flights, so OO 3859 is about level with it. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 14 points.

OO 3859 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3859thin sample	364	92.5%	51 min	1.37%	A
All SkyWest Airlines on GTF–SLC	1,071	92.3%	78 min	0.75%	A+
All carriers on GTF–SLC	1,071	92.3%	78 min	0.75%	A+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 3859 quarter by quarter

Quarter by quarter OO 3859 held fairly steady: 93.5% in Jul–Sep 2025, 93.1% in Oct–Dec 2025, 88.8% in Jan–Mar 2026 and 94.5% in Apr–Jun 2026. A spread of 6 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights93.5%
Oct–Dec 202591 flights93.1%
Jan–Mar 202690 flights88.8%
Apr–Jun 202691 flights94.5%

Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, OO 3859 ranged from 88.5% on Monday to 98.1% on Tuesday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why OO 3859 runs late

One category carries most of the weight here. Extreme weather accounts for 57% of the 1,363 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.

Extreme weather
57%
Carrier
39%
National Airspace System
4%

Extreme weather accounts for 57% 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 9.2 times the usual weather exposure. The split is drawn from 1,363 delay minutes reported on OO 3859.

Cancellations sit at 1.37% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 1.9% 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.

OO 3859 is not only a GTF to SLC flight. It also flew SLC to GTF (364 flights, 95.5% 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. 364 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.

Other routes flown as OO 3859
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
SLC to GTFthin sample	364	95.5%	63 min	1.37%	A

What to do with this

Booking OO 3859

For a booking, OO 3859 has one of the better records a US domestic flight can show: 92.5% on time and 1.37% 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