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DelayAtlas

Route reliability record

SEAOAK

Seattle to Oakland

Flights
1,917
Period
July 2025 to June 2026
Distance
672 mi
Carriers
3
C+GRADE

This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 1,917 SEA to OAK flights, of which Alaska Airlines flew 700 at 75.3% on time.

Best time to fly SEA to OAK: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 96.5% of the time and Saturday flights 82.9%, against 73.4% for the route overall.

The national on-time rate over the same period is 77.6%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 42 extra late arrivals.

Key figures

On time

73.4%

Arrivals under 15 minutes late, of 1,903 completed flights

Avg delay

51 min

Across delayed arrivals only, not all flights

Cancelled

0.73%

National rate is 1.81%

Best carrier

Alaska

75.3% on time across 700 flights

These figures cover 1,917 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.

Carrier by carrier

Which airline is most reliable on SEA to OAK

The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on SEA to OAK
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlinesthin sample9081.8%51 min2.22%B
Alaska Airlines70075.3%45 min1.57%B
Southwest Airlines1,12771.6%54 min0.09%C+

No carrier stands out. Alaska tops the table at 75.3%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Best ways to make this trip

The most reliable ways to fly Seattle to Oakland

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.

Most reliable ways to fly from SEA to OAK
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. SEASJCSeattle to San JoseSkyWest Airlines87.8%88.0%0.19%8am–11am, WedOO 3789 11:45
2. SEASJCSeattle to San JoseAlaska Airlines79.4%80.6%1.55%5am–8am, Wed
3. SEASFOSeattle to San FranciscoSkyWest Airlines74.6%75.4%1.02%5am–8am, SatOO 3707 13:40
4. SEAOAKSeattle to OaklandAlaska Airlines74.1%75.3%1.57%2pm–5pm, Tue
5. SEASJCSeattle to San JoseSouthwest Airlines72.4%72.6%0.32%8am–11am, Wed

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 41 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am202 flights96.5%
  • 8am–11am382 flights83.5%
  • 11am–2pm369 flights71.0%
  • 2pm–5pm223 flights75.7%
  • 5pm–8pm306 flights55.6%
  • 8pm–5am435 flights67.1%

Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 55.6% on time, against 96.5% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 435 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 18 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

On-time rate by calendar month82J82F76M82A76M70J65J64A71S80O79N65D
Darker means more delays. Figures are on-time percentages.February best, August worst

August is the worst month at 64.1% on time, 18 points below February, the best at 82.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 233 flights.

Across the week, Saturday is the strongest day at 82.9% on time and Thursday the weakest at 66.2%. 17 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week67.8Mon80.6Tue79.9Wed66.2Thu70.1Fri82.9Sat69.0Sun
Monday: 67.8 percent on time. Tuesday: 80.6 percent on time. Wednesday: 79.9 percent on time. Thursday: 66.2 percent on time. Friday: 70.1 percent on time. Saturday: 82.9 percent on time. Sunday: 69.0 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 57% of the 26,000 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
    57%
  • Carrier
    34%
  • National Airspace System
    7%
  • Security
    0%
  • Extreme weather
    0%

57% 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 26,000 reported delay minutes here, that single category outweighs weather by 57 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 25,726 reported delay minutes.

The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 8,824 of the 26,000 delay minutes reported here.

Cancellations are rare at 0.73%, 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 stage length

What a delay here actually costs

6.1% 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 about 50 minutes, which a normal layover absorbs.

The 672 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 77.3% on time across 1,901 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.

The sample behind these figures is 1,917 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

Work out the risk of missing a connection in OAK after this flight

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 82.4% on time and August 64.1%, a swing of 18 points. If the dates move at all, move them out of August before you think about anything else. 1,903 completed flights over 12 months sit behind that.

Common questions

SEA to OAK questions

How often is SEA to OAK delayed?

About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.6% of the 1,917 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.

Which airline is most reliable on SEA to OAK?

Alaska Airlines leads at 75.3% on time across 700 flights. Southwest Airlines is at the other end on 71.6%, a gap of 4 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on SEA to OAK?

The 5am–8am departure window is the strongest at 96.5% on time. The 5pm–8pm window is the weakest at 55.6%, 41 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are August delays on SEA to OAK?

August is the weakest month at 64.1% on time, compared with 82.4% in February. Across the year that is 18 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Related

Where to go next

Direction matters. SEA to OAK and OAK to SEA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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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.