Flight number record

OO 3855

SkyWest Airlines · Seattle to Eugene

Route: SEA → EUG
Departs: 21:55
Flights: 361
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 3855, 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 3855 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 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 361 flights, with a median arrival 11 minutes early.

Set against the rest of the country, OO 3855's record is 11 points better than the US average of 77.6%. That gap is worth roughly 113 fewer late arrivals for every thousand flights.

On time

88.9%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

1 hour+ late

3.3%

National rate is 8.1%

These figures cover 361 flights between July 2025 and June 2026. The median arrival is 11 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 3855 flies

OO 3855 flies SEA to EUG without a single fixed slot. Its most common scheduled departure was 21:55, used on 104 of 361 flights, with 22:35 (88 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 21:55104 flights28.8%
Departs 22:3588 flights24.4%

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 21:55 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and OO 3855 runs 18 points better at 88.9%. 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 3855 next to SEA to EUG

Every carrier on SEA to EUG combined arrived on time 84.4% of the time across 1,951 flights, so OO 3855 is 5 points ahead of it. SkyWest flew 1,562 flights on the same city pair under all its flight numbers, including this one, and those ran 87.1% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight beats by 10 points.

OO 3855 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3855thin sample	361	88.9%	79 min	0.00%	A+
All SkyWest Airlines on SEA–EUG	1,562	87.1%	61 min	1.34%	A
All carriers on SEA–EUG	1,951	84.4%	55 min	1.28%	B
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 3855 quarter by quarter

OO 3855 did not run the same all year. Its best quarter was Oct–Dec 2025 at 94.4% on time and its weakest Jan–Mar 2026 at 81.1%, a swing of 13 points on roughly 90 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 202590 flights88.9%
Oct–Dec 202590 flights94.4%
Jan–Mar 202690 flights81.1%
Apr–Jun 202691 flights91.2%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, OO 3855 ranged from 84.3% on Friday to 92.0% on Saturday. 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 3855 runs late

One category carries most of the weight here. Carrier accounts for 74% of the 3,140 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
74%
Extreme weather
22%
National Airspace System
5%

Extreme weather accounts for 22% 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 3.5 times the usual weather exposure. The split is drawn from 3,140 delay minutes reported on OO 3855.

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 3.3% 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 361 flights under OO 3855 in the data flew SEA to EUG. 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. 361 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 3855

For a booking, OO 3855 has one of the better records a US domestic flight can show: 88.9% 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