Flight number record

OO 3918

SkyWest Airlines · Portland to Seattle

Route: PDX → SEA
Departs: 17:50
Flights: 324
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s OO 3918, 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 3918 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 45 minutes. That rests on 324 flights, with a median arrival 10 minutes early.

Set against the rest of the country, OO 3918's record is 7 points better than the US average of 77.3%. That gap is worth roughly 69 fewer late arrivals for every thousand flights.

On time

84.2%

Arrivals under 15 minutes late, of 323 completed flights

Avg delay

44 min

Across delayed arrivals only, not all flights

Cancelled

0.31%

National rate is 1.89%

1 hour+ late

2.5%

National rate is 8.3%

These figures cover 324 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 3918 flies

OO 3918 flies PDX to SEA without a single fixed slot. Its most common scheduled departure was 17:50, used on 80 of 324 flights, with 17:15 (56 flights) and 17:36 (36 flights) next.

Departs 17:5080 flights24.7%
Departs 17:1556 flights17.3%
Departs 17:3636 flights11.1%

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 17:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and OO 3918 runs 16 points better at 84.2%. 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 3918 next to PDX to SEA

Every carrier on PDX to SEA combined arrived on time 84.9% of the time across 4,927 flights, so OO 3918 is about level with it. SkyWest flew 3,472 flights on the same city pair under all its flight numbers, including this one, and those ran 85.5% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 6 points.

OO 3918 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3918thin sample	324	84.2%	44 min	0.31%	B+
All SkyWest Airlines on PDX–SEA	3,472	85.5%	59 min	0.58%	A+
All carriers on PDX–SEA	4,927	84.9%	54 min	0.71%	B+
SkyWest Airlines, whole network	855,406	78.7%	88 min	1.79%	B

Across the year

OO 3918 quarter by quarter

OO 3918 did not run the same all year. Its best quarter was Oct–Dec 2025 at 93.7% on time and its weakest Apr–Jun 2026 at 76.1%, a swing of 18 points on roughly 65 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 flights90.0%
Oct–Dec 202579 flights93.7%
Jan–Mar 202686 flights84.7%
Apr–Jun 202667 flights76.1%
Jul–Sep 202662 flights77.4%

Scale runs 70% to 100%.

By weekday, OO 3918 did best on Saturday at 97.8% on time and worst on Thursday at 69.6%. Each day rests on about 46 flights, so a gap of 28 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late OO 3918 runs when it is late

OO 3918 often beats the schedule: 120 of 323 completed flights, 37%, arrived 15 minutes or more early. Most of the lateness is short. 27 of the 51 late arrivals were under half an hour behind, and 8 reached an hour or more.

15+ min early120 flights37.2%
Within 15 min152 flights47.1%
15–29 min late27 flights8.4%
30–59 min late16 flights5.0%
1–2 hours late4 flights1.2%
2+ hours late4 flights1.2%

Scale runs 0% to 100%.

Share of 323 completed flights by arrival against schedule.

5 of 36 late departures made up the time and arrived on time, 14% of them. In the other direction, 20 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SEA.

The worst days

Worst days for OO 3918

The latest arrival of the period was on 30 March 2026, 4 hours 32 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as extreme weather.

The latest arrivals of OO 3918 in the period
Date	Arrived late by	Largest filed cause
30 March 2026	4 hours 32 minutes	Carrier
16 January 2026	2 hours 27 minutes	Extreme weather
10 April 2026	2 hours 11 minutes	Carrier
3 March 2026	2 hours 9 minutes	Extreme weather
17 May 2026	1 hour 42 minutes	Extreme weather

Delay causes

Why OO 3918 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 2,246 reported delay minutes.

Carrier
38%
Extreme weather
37%
National Airspace System
24%
Security
1%

Extreme weather accounts for 37% 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 6.1 times the usual weather exposure. The split is drawn from 2,246 delay minutes reported on OO 3918.

Cancellations are rare at 0.31%, 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 2.5% 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.

OO 3918 is not only a PDX to SEA flight. It also flew SEA to PDX (323 flights, 83.5% 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. 324 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 3918
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
SEA to PDXthin sample	323	83.5%	43 min	0.31%	B+

What to do with this

Booking OO 3918

For a booking, read OO 3918 as 84.2% on time with 0.31% cancelled over 324 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures