Flight number record

OO 3855

SkyWest Airlines · Seattle to Eugene

Route: SEA → EUG
Departs: 22:35
Flights: 362
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 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 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 362 flights, with a median arrival 10 minutes early.

Set against the rest of the country, OO 3855's record is 10 points better than the US average of 77.3%. That gap is worth roughly 102 fewer late arrivals for every thousand flights.

On time

87.5%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

82 min

Across delayed arrivals only, not all flights

Cancelled

0.28%

National rate is 1.89%

1 hour+ late

3.3%

National rate is 8.3%

These figures cover 362 flights between September 2025 and August 2026. The median arrival is 10 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.

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Schedule

When OO 3855 flies

OO 3855 flies SEA to EUG without a single fixed slot. Its most common scheduled departure was 22:35, used on 116 of 362 flights, with 21:55 (104 flights) next.

Departs 22:35116 flights32.0%
Departs 21:55104 flights28.7%

Scale runs 0% to 100%.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 22:35 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and OO 3855 runs 17 points better at 87.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

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Against the route

OO 3855 next to SEA to EUG

Every carrier on SEA to EUG combined arrived on time 84.2% of the time across 1,894 flights, so OO 3855 is 3 points ahead of it. SkyWest flew 1,629 flights on the same city pair under all its flight numbers, including this one, and those ran 84.6% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 9 points.

OO 3855 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3855thin sample	362	87.5%	82 min	0.28%	A+
All SkyWest Airlines on SEA–EUG	1,629	84.6%	64 min	1.35%	B
All carriers on SEA–EUG	1,894	84.2%	60 min	1.32%	B
SkyWest Airlines, whole network	855,406	78.7%	88 min	1.79%	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 72 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 202530 flights86.7%
Oct–Dec 202590 flights94.4%
Jan–Mar 202690 flights81.1%
Apr–Jun 202691 flights91.2%
Jul–Sep 202661 flights81.7%

Scale runs 75% to 100%.

By weekday, OO 3855 ranged from 82.4% on Thursday to 94.2% on Tuesday. With about 52 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late OO 3855 runs when it is late

OO 3855 often beats the schedule: 126 of 361 completed flights, 35%, arrived 15 minutes or more early. The 45 late arrivals split 18 under half an hour, 15 between 30 and 60 minutes, and 12 an hour or more.

15+ min early126 flights34.9%
Within 15 min190 flights52.6%
15–29 min late18 flights5.0%
30–59 min late15 flights4.2%
1–2 hours late7 flights1.9%
2+ hours late5 flights1.4%

Scale runs 0% to 100%.

Share of 361 completed flights by arrival against schedule.

7 of 45 late departures made up the time and arrived on time, 16% of them. Only 7 left on time and still arrived late.

The worst days

Worst days for OO 3855

The latest arrival of the period was on 21 February 2026, 12 hours 43 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.

The latest arrivals of OO 3855 in the period
Date	Arrived late by	Largest filed cause
21 February 2026	12 hours 43 minutes	Carrier
6 March 2026	9 hours 5 minutes	Carrier
2 August 2026	8 hours 15 minutes	Carrier
4 January 2026	3 hours 52 minutes	Extreme weather
6 August 2026	2 hours 20 minutes	Carrier

Delay causes

Why OO 3855 runs late

Carrier accounts for 79% of the 3,698 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
79%
Extreme weather
18%
National Airspace System
3%

Extreme weather accounts for 18% 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 3.0 times the usual weather exposure. The split is drawn from 3,698 delay minutes reported on OO 3855.

Cancellations are rare at 0.28%, below the national 1.89% 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

Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.3% 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 362 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. 362 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: 87.5% on time and 0.28% 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures