Flight number record

OO 5566

SkyWest Airlines · San Francisco to Sacramento

Route: SFO → SMF
Departs: 22:45
Flights: 256
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 5566, 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 5566 lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 256 flights, with a median arrival 2 minutes early.

On time

77.5%

Arrivals under 15 minutes late, of 253 completed flights

Avg delay

95 min

Across delayed arrivals only, not all flights

Cancelled

0.78%

National rate is 1.81%

1 hour+ late

5.9%

National rate is 8.1%

These figures cover 256 flights between July 2025 and June 2026. The median arrival is 2 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 5566 flies

OO 5566 flies SFO to SMF without a single fixed slot. Its most common scheduled departure was 22:45, used on 57 of 256 flights, with 22:58 (49 flights) and 21:00 (41 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 22:4557 flights22.3%
Departs 22:5849 flights19.1%
Departs 21:0041 flights16.0%

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 22:45 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and OO 5566 runs 7 points better at 77.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

OO 5566 next to SFO to SMF

Every carrier on SFO to SMF combined arrived on time 78.9% of the time across 1,377 flights, so OO 5566 is about level with it. SkyWest flew 1,323 flights on the same city pair under all its flight numbers, including this one, and those ran 79.3% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight trails by 2 points.

OO 5566 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 5566thin sample	256	77.5%	95 min	0.78%	B+
All SkyWest Airlines on SFO–SMF	1,323	79.3%	79 min	1.74%	B
All carriers on SFO–SMF	1,377	78.9%	77 min	1.67%	B
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 5566 quarter by quarter

OO 5566 did not run the same all year. Its best quarter was Jan–Mar 2026 at 86.8% on time and its weakest Apr–Jun 2026 at 68.0%, a swing of 19 points on roughly 64 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 202574 flights72.6%
Oct–Dec 202563 flights80.6%
Jan–Mar 202669 flights86.8%
Apr–Jun 202650 flights68.0%

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, OO 5566 did best on Thursday at 85.0% on time and worst on Sunday at 63.2%. Each day rests on about 37 flights, so a gap of 22 points is worth noticing but could still narrow in another year.

Delay causes

Why OO 5566 runs late

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 5,385 reported delay minutes.

National Airspace System
33%
Extreme weather
31%
Late-arriving aircraft
25%
Carrier
11%

Extreme weather accounts for 31% 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 5.0 times the usual weather exposure. The split is drawn from 5,385 delay minutes reported on OO 5566.

Cancellations are rare at 0.78%, 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

5.9% 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 an hour and a half, which a normal layover absorbs.

The same number turns up on four other city pairs in the data, including MKE to ORD (32), ORD to TVC (24) and ORD to CRW (6), but none flew often enough under OO 5566 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SFO to SMF only.

One caution: this is a thin sample. 256 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 5566

For a booking, read OO 5566 as 77.5% on time with 0.78% cancelled over 256 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