Flight number record

OO 3439

SkyWest Airlines · San Diego to Sacramento

Route: SAN → SMF
Departs: 12:30
Flights: 250
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 3439, 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 3439 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 250 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so OO 3439 runs 6 points behind the country as a whole. Across a thousand flights that is about 59 extra late arrivals.

On time

71.7%

Arrivals under 15 minutes late, of 247 completed flights

Avg delay

47 min

Across delayed arrivals only, not all flights

Cancelled

0.80%

National rate is 1.81%

1 hour+ late

8.1%

National rate is 8.1%

These figures cover 250 flights between July 2025 and June 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Schedule

When OO 3439 flies

OO 3439 flies SAN to SMF without a single fixed slot. Its most common scheduled departure was 12:30, used on 52 of 250 flights, with 12:32 (43 flights) and 13:10 (30 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 12:3052 flights20.8%
Departs 12:3243 flights17.2%
Departs 13:1030 flights12.0%

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 12:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and OO 3439 runs 7 points worse at 71.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

OO 3439 next to SAN to SMF

Every carrier on SAN to SMF combined arrived on time 76.4% of the time across 5,177 flights, so OO 3439 is 5 points behind it. SkyWest flew 1,185 flights on the same city pair under all its flight numbers, including this one, and those ran 79.5% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight trails by 7 points.

OO 3439 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3439thin sample	250	71.7%	47 min	0.80%	C+
All SkyWest Airlines on SAN–SMF	1,185	79.5%	49 min	1.35%	B
All carriers on SAN–SMF	5,177	76.4%	47 min	0.81%	B+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 3439 quarter by quarter

OO 3439 did not run the same all year. Its best quarter was Jan–Mar 2026 at 81.2% on time and its weakest Jul–Sep 2025 at 58.1%, a swing of 23 points on roughly 63 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 202543 flights58.1%
Oct–Dec 202574 flights64.4%
Jan–Mar 202666 flights81.2%
Apr–Jun 202667 flights79.1%

Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.

By weekday, OO 3439 did best on Tuesday at 87.5% on time and worst on Friday at 56.4%. Each day rests on about 36 flights, so a gap of 31 points is worth noticing but could still narrow in another year.

Delay causes

Why OO 3439 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 51% of the 3,271 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.

Late-arriving aircraft
51%
National Airspace System
35%
Carrier
11%
Extreme weather
3%

51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 3,271 reported delay minutes here, that single category outweighs weather by 18 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 3,271 delay minutes reported on OO 3439.

Cancellations are rare at 0.80%, below the national 1.81% 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

8.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 45 minutes, which a normal layover absorbs.

The same number turns up on two other city pairs in the data, including SMF to SAN (211) and PDX to SEA (39), but none flew often enough under OO 3439 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SAN to SMF only.

One caution: this is a thin sample. 250 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 3439

For a booking, read OO 3439 as 71.7% on time with 0.80% cancelled over 250 flights. Those are rates from the past twelve months, not a forecast for any particular 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