Carrier route record

ASSMF→SEA

Alaska Airlines · Sacramento to Seattle

Flights: 1,309
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 SMF to SEA lands a B+, 3 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 roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 1,309 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,952 at 87.4% on time.

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

On time

80.3%

Arrivals under 15 minutes late, of 1,301 completed flights

Avg delay

42 min

Across delayed arrivals only, not all flights

Cancelled

0.61%

National rate is 1.81%

Whole route

82.7%

Every carrier on SMF to SEA, 4,416 flights

These figures cover 1,309 flights between July 2025 and June 2026. The median arrival is 5 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 SMF to SEA

Alaska flew 1,309 of the 4,416 flights on SMF to SEA, about 30% of it. Its 80.3% on time is 2 points worse than the route as a whole, which runs 82.7%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 87.4% to Southwest at 77.4%.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 87.4% of the time; Southwest Airlines manages 77.4%. Sample sizes sit next to every figure, because a two-point gap across 1,155 flights means less than a ten-point one.

On-time performance by carrier on SMF to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	1,952	87.4%	57 min	0.26%	A+
Alaska Airlines (this page)	1,309	80.3%	42 min	0.61%	B+
Southwest Airlines	1,155	77.4%	43 min	0.17%	B+

SkyWest leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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 27 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am289 flights90.9%
8am–11am353 flights77.4%
11am–2pm271 flights86.3%
2pm–5pm140 flights63.8%
5pm–8pm154 flights75.3%
8pm–5am102 flights74.5%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.9% of the time, against 63.8% for the afternoon window. That is 27 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 353 flights scheduled in it.

Across the year

Alaska on SMF to SEA through the year

Darker means more delays. Figures are on-time percentages.February best, September worst

Delays peak in September, when the on-time rate falls to 68.1%. February is the strongest month at 92.0%. Moving a flexible trip across that boundary buys 24 points. June was the busiest month here, with 146 flights.

Across the week, Tuesday is the strongest day at 86.7% on time and Thursday the weakest at 76.6%. 10 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. National Airspace System accounts for 43% of the 11,000 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.

National Airspace System
43%
Late-arriving aircraft
29%
Carrier
27%
Extreme weather
0%
Security
0%

43% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 4,639 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 10,693 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 90.9% on time 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 3.0% 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 79.8% on time across 1,310 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 1,309 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 SMF to SEA

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 92.0% on time and September 68.1%, a swing of 24 points. If the dates move at all, move them out of September before you think about anything else. 1,301 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