SJC → SEA Flight Reliability

Right now

Origin · SJCNo disruption reported

Aviation weather is not currently a factor.

Updated 08:53 UTC

San Jose airport profile →

Destination · SEANo disruption reported

Aviation weather is not currently a factor.

Updated 08:53 UTC

Seattle airport profile →

Route reliability

July 2023 – July 2026

Route Reliability Score

82/ 100Strong

Better than 90% of comparable major US routes (4,598 compared)

Calculated from 13,899 flights. How this is calculated

On-time arrivals

83.9%

11,558 of 13,772

Cancellation rate

0.80%

111 cancelled

Median arrival delay

-8 min

Average -0.7 min

Severe delays

3.8%

60+ minutes late

Delay when late

52 min

Average, when 15+ min late

Flights analyzed

13,899

3 carriers

SJC → SEA arrives on time 83.9% of the time; the return trip, SEA → SJC, arrives on time 81.3% of the time, a 2.6-point gap between the two directions of the same city pair.

SJC → SEA spends 28.3 minutes on the ground on a 696-mile trip: 16.3 minutes from pushback to wheels-up at SJC and 12.0 minutes from touchdown to gate at SEA.

Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026

What stands out

This route has stayed remarkably steady year over year, a smaller swing than 92% of 5,368 comparable routes.

83.4% on time over the most recent 12 months (2025-08 to 2026-07), against 83.9% in the 12 months before (2024-08 to 2025-07), virtually unchanged.

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 5,368 in the comparison.

Why SJC → SEA flights are cancelled

July 2023 – July 2026

SJC → SEA cancelled 111 of 13,899 scheduled flights — about 1 in every 125. The reason filed most often was the airline, 84.7% of the cancellations coded on this route — about 1 in every 148 scheduled flights.

Share of cancellations

Airline84.7%

Weather13.5%

Air traffic1.8%

Security0.0%

Of 111 cancelled departures carrying a reason code.

What each reason means

The airline1 in 148

Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.

94 cancellations, 84.7% of the total.

Extreme weather1 in 927

Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.

15 cancellations, 13.5% of the total.

The air traffic system1 in 6,950

Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.

2 cancellations, 1.8% of the total.

Security—

A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.

0 cancellations, 0.0% of the total.

Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.

111 coded cancellations were recorded on SJC → SEA; the section appears from 50.

When it goes wrong

July 2023 – July 2026

One arrival in ten is worse than

27 min late

against a median of 8 min early

Arrived an hour or more late3.8%

Typical delay when late52 min

Cancelled0.80%

Landed somewhere else0.12%

Percentiles over 13,899 operations; cancelled and diverted flights are counted separately.

Will your connection be tight enough?

Layovers at SEA after arriving from SJC.

Connection buffer and chance of missing by layover length, SJC → SEA arrivals
Connection time	Chance of missing	Reads as
30 min	32%	Likely to miss
45 min	16%	High risk
60 min	8.8%	Some risk
90 min	3.8%	Low risk
120 min	2.0%	Low risk

This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.80% of the time and diverts 0.12% of the time, which a late arrival never shows up in.

Chance of missing is the share of 13,772 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.

The worst tenth of arrivals on this route land at least 27 minutes late (90th-percentile gate arrival delay), over 13,899 operations.

Any other layover length: connection checker.

Best time to fly

SJC → SEA flights departing 5–9 AM arrived on time 90.1% of the time, against 72.6% for 9 PM–5 AM departures, a gap of 17.5 percentage points.

By day and hour

On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (SJC).

Hour of departure matters more than day of the week: hourly averages sit a typical 7.1 points from the route-wide rate, weekday averages 2.6 points.

On-time arrival rate for SJC to SEA by weekday and scheduled departure hour, local time. Each button reads out one slot.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
6 AM–7 AM
7 AM–8 AM
8 AM–9 AM
9 AM–10 AM
10 AM–11 AM
11 AM–12 PM
12 PM–1 PM
1 PM–2 PM
2 PM–3 PM
3 PM–4 PM
4 PM–5 PM
5 PM–6 PM
6 PM–7 PM
7 PM–8 PM
8 PM–9 PM
9 PM–10 PM

On-time rate, % · stronger color, fewer on time

65–69
70–74
75–79
80–84
85–89
90–94
95–99

Fewer than 120 flights, not scored

Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · On time is arrival within 15 minutes of schedule. Cells round to whole percentages; the table shows one decimal.

No slot is named best or worst: too few reach 500 flights. Departures after 10 PM (50 flights) are not drawn: no slot in those hours has enough flights to score.

View as tableHide table

On-time arrival rate (%) with flights beneath, by scheduled departure hour and weekday for SJC to SEA. A dash means fewer than 120 flights, which are not scored.
Hour	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
6 AM–7 AM	94.1% on time257 flights	94.3% on time214 flights	94.8% on time214 flights	94.6% on time262 flights	97.2% on time255 flights	96.0% on time201 flights	95.5% on time245 flights
7 AM–8 AM	94.7% on time132 flights	90.4% on time156 flights	94.2% on time158 flights	90.0% on time130 flights	89.6% on time134 flights	90 flights, too few to score	115 flights, too few to score
8 AM–9 AM	99 flights, too few to score	74.8% on time121 flights	76.5% on time120 flights	101 flights, too few to score	98 flights, too few to score	51 flights, too few to score	96 flights, too few to score
9 AM–10 AM	71 flights, too few to score	33 flights, too few to score	35 flights, too few to score	70 flights, too few to score	68 flights, too few to score	40 flights, too few to score	38 flights, too few to score
10 AM–11 AM	91.4% on time187 flights	94.4% on time178 flights	88.0% on time179 flights	83.6% on time186 flights	83.5% on time185 flights	87.7% on time141 flights	86.9% on time175 flights
11 AM–12 PM	87.4% on time135 flights	95.1% on time143 flights	92.5% on time146 flights	83.0% on time141 flights	86.6% on time134 flights	119 flights, too few to score	119 flights, too few to score
12 PM–1 PM	91.6% on time122 flights	119 flights, too few to score	86.7% on time120 flights	113 flights, too few to score	84.4% on time124 flights	99 flights, too few to score	109 flights, too few to score
1 PM–2 PM	57 flights, too few to score	45 flights, too few to score	43 flights, too few to score	54 flights, too few to score	57 flights, too few to score	49 flights, too few to score	43 flights, too few to score
2 PM–3 PM	83.3% on time229 flights	86.2% on time240 flights	85.5% on time241 flights	78.4% on time236 flights	82.0% on time230 flights	81.6% on time136 flights	82.9% on time206 flights
3 PM–4 PM	75.0% on time125 flights	106 flights, too few to score	111 flights, too few to score	119 flights, too few to score	113 flights, too few to score	81 flights, too few to score	77.6% on time125 flights
4 PM–5 PM	41 flights, too few to score	49 flights, too few to score	49 flights, too few to score	41 flights, too few to score	49 flights, too few to score	97 flights, too few to score	91 flights, too few to score
5 PM–6 PM	86.8% on time153 flights	87.3% on time157 flights	81.5% on time159 flights	80.4% on time148 flights	85.8% on time142 flights	88.2% on time120 flights	80.1% on time137 flights
6 PM–7 PM	81.7% on time198 flights	82.3% on time250 flights	81.4% on time248 flights	71.6% on time208 flights	80.7% on time205 flights	77.8% on time173 flights	78.4% on time193 flights
7 PM–8 PM	114 flights, too few to score	71 flights, too few to score	68 flights, too few to score	93 flights, too few to score	89 flights, too few to score	82 flights, too few to score	112 flights, too few to score
8 PM–9 PM	114 flights, too few to score	50 flights, too few to score	58 flights, too few to score	66.1% on time121 flights	115 flights, too few to score	63 flights, too few to score	88 flights, too few to score
9 PM–10 PM	80 flights, too few to score	29 flights, too few to score	27 flights, too few to score	82 flights, too few to score	77 flights, too few to score	54 flights, too few to score	68.0% on time130 flights

By departure window

5–9 AM90.1%

9 AM–12 PM87.6%

12–3 PM84.1%

3–6 PM83.6%

6–9 PM75.5%

9 PM–5 AM72.6%

By departure hour

12 AM

3 AM

6 AM

9 AM

12 PM

3 PM

6 PM

9 PM

Why SJC → SEA runs late

July 2023 – July 2026

The airline35.9%

crew, maintenance, boarding and fueling, all within the carrier’s control

Late-arriving aircraft35.9%

the inbound aircraft was late, so this flight started late

Air traffic control20.7%

airspace and airport capacity, including weather-driven flow control

Weather7.2%

weather severe enough to stop this flight specifically

Security0.2%

screening or terminal security incidents

Share of the delay minutes US DOT attributed to each cause for SJC → SEA. Only delays of 15 minutes or more are attributed.

How this route holds up in bad weather

July 2023 – July 2026

Bad weather raises cancellations by a similar amount at both ends of SJC to SEA: 1.6 times the normal rate at SJC and 1.9 times at SEA. Cancelled in bad weather against normal hours: SJC 1.0% against 0.6%, SEA 1.5% against 0.8%. Flights that did leave SEA in bad weather arrived on time 75.4% of the time, against 79.3% in normal hours.

Bad weather and normal hours at the airports

Scheduled departures, July 2023 – July 2026

Departures from SJC and SEA in hours of bad weather and in normal hours
Departures from	SJC	SEA
Cancelled in bad weather	1.0%	1.5%
Cancelled in normal hours	0.6%	0.8%
Arrived on time, bad weather	87.4%	75.4%
Arrived on time, normal hours	83.5%	79.3%
Departures in bad weather	4,322	43,416

These are airport figures, not route figures: every scheduled departure from SJC and SEA, to any destination, in hours the weather report called bad.

Weather source and limits. In full: SJC, SEA, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.

Airlines on this route

Carriers with at least 200 flights, by the airline that operated each one.

Airlines on this route
Carrier	Flights	On time	Cancelled	Median delay	Severe
Alaska Airlines	5,865	83.6%	1.74%	-7 min	3.7%
SkyWest Airlines	4,522	88.8%	0.09%	-11 min	3.4%
Southwest Airlines	3,396	77.7%	0.06%	-4 min	4.5%

Alaska Airlines flew 42.6% of the 13,783 flights listed. Alaska Airlines cancelled 1.74% of its flights here against 0.06% for Southwest Airlines.

SkyWest Airlines arrived on time 11.1 percentage points more often than Southwest Airlines on this route.

Other ways to fly San Francisco to Seattle

Airport pairs in the same two city markets, as the DOT defines them.

Other ways to fly San Francisco to Seattle
Route	Flights	On time	Cancelled	Median delay	Score
SFO→SEA San Francisco to Seattle	20,767	75.9%	1.16%	-5 min	65
SJC→SEA this route San Jose to Seattle	13,899	83.9%	0.80%	-8 min	82

SJC → SEA is the most reliable pairing for this journey at 83.9% on time, against 75.9% for SFO → SEA.

Flying to SEA from the San Francisco area? Compare SJC, SFO, OAK for SEA, with the same test for what counts as a real difference.

Weekly and seasonal patterns

By day of week

Mon84.4%

Tue87.8%

Wed86.1%

Thu80.2%

Fri82.2%

Sat85.8%

Sun81.6%

Tuesday is historically the most reliable day and Thursday the least, a gap of 7.6 percentage points.

By month

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

June is historically the weakest month and February the strongest, a spread of 13.4 percentage points.

Reliability over time

July 2023 – July 2026

24

25

26

Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 83.4% against 83.9% in the 12 months before — broadly unchanged.

Data and methodology

Calculated by FlyerIntel from 13,899 SJC → SEA flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.

Full methodology · Data sources · Report a problem

Analysis last recomputed September 26, 2026

SJC airport SEA airport Return direction SEA → SJC

SJC→SEA

Right now

Route reliability

What stands out

Why SJC → SEA flights are cancelled

Share of cancellations

What each reason means

When it goes wrong

Will your connection be tight enough?

Best time to fly

By day and hour

By departure window

By departure hour

Why SJC → SEA runs late

How this route holds up in bad weather

Bad weather and normal hours at the airports

Airlines on this route

Other ways to fly San Francisco to Seattle

Weekly and seasonal patterns

By day of week

By month

Reliability over time

Data and methodology