Carrier route record

ASSEA→SMF

Alaska Airlines · Seattle to Sacramento

Flights: 1,310
Period: July 2025 to June 2026
Share of route: 30%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.

Alaska on SEA to SMF lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 1,310 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,941 at 89.3% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SEA to SMF from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

79.8%

Arrivals under 15 minutes late, of 1,300 completed flights

Avg delay

44 min

Across delayed arrivals only, not all flights

Cancelled

0.61%

National rate is 1.81%

Whole route

81.9%

Every carrier on SEA to SMF, 4,407 flights

These figures cover 1,310 flights between July 2025 and June 2026. The median arrival is 3 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

Alaska against every carrier on SEA to SMF

Alaska flew 1,310 of the 4,407 flights on SEA to SMF, about 30% of it. Its 79.8% on time is 2 points worse than the route as a whole, which runs 81.9%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 89.3% to Southwest at 71.9%.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 89.3% of the time; Southwest Airlines manages 71.9%. Sample sizes sit next to every figure, because a two-point gap across 1,156 flights means less than a ten-point one.

On-time performance by carrier on SEA to SMF
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	1,941	89.3%	62 min	0.26%	A+
Alaska Airlines (this page)	1,310	79.8%	44 min	0.61%	B+
Southwest Airlines	1,156	71.9%	48 min	0.43%	C+

The spread between SkyWest and Southwest is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.

Departure window

When Alaska runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am21 flights—
8am–11am208 flights86.5%
11am–2pm326 flights82.4%
2pm–5pm129 flights81.2%
5pm–8pm133 flights73.5%
8pm–5am493 flights76.1%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 86.5% of the time, against 73.5% for the evening window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 493 flights scheduled in it.

Across the year

Alaska on SEA to SMF through the year

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 66.9% on time, 25 points below April, the best at 92.0%. 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. June was the busiest month here, with 147 flights.

Across the week, Saturday is the strongest day at 83.6% on time and Sunday the weakest at 75.6%. 8 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Alaska runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 12,000 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
49%
Carrier
40%
National Airspace System
9%
Extreme weather
1%

49% 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 12,000 reported delay minutes here, that single category outweighs weather by 36 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 11,594 reported delay minutes.

The largest share of delay minutes, 40%, 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 4,664 of the 12,000 delay minutes reported here.

Cancellations are rare at 0.61%, 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 costs

Badly late arrivals are rare here: only 3.8% 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.

The 605 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 runs 80.3% on time across 1,309 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,310 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.

What to do with this

Booking Alaska on SEA to SMF

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 92.0% on time and July 66.9%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 1,300 completed flights over 12 months sit behind that.

Where to go next

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