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DelayAtlas

Carrier performance at one airport

WNSMF

Southwest Airlines at Sacramento International

Departures
32,217
Period
June 2025 to May 2026
Routes
25
Rank here
#7 of 8
B+GRADE

Southwest Airlines at Sacramento lands a B+, 3 points better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about 50 minutes on average. That is a workable record, not a spotless one. That rests on 32,217 flights, of which Delta Air Lines flew 3,494 at 91.2% on time.

Measured against the airport rather than the country, Southwest Airlines runs 2 points behind the 82.3% weighted average across all carriers at SMF. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

Key figures

On time

80.5%

31,999 completed departures

Avg delay

49 min

Across delayed flights only

Cancelled

0.47%

At SMF, this carrier only

Rank here

#7

Of 8 carriers clearing the floor at SMF

These figures cover 32,000 flights between June 2025 and May 2026. The median arrival is 4 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.

Against the competition

Every carrier at SMF, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 91.2% of the time; Frontier Airlines manages 77.5%. Sample sizes sit next to every figure, because a two-point gap across 542 flights means less than a ten-point one.

On-time performance of all carriers departing SMF
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines3,49491.2%87 min0.94%A+
United Airlines4,33885.9%66 min0.60%A+
SkyWest Airlines9,45483.8%69 min0.81%B+
Hawaiian Airlines64382.7%72 min0.93%B+
American Airlines3,69082.1%93 min1.63%B
Alaska Airlines2,18481.4%48 min0.87%B+
Southwest Airlines (this page)32,21780.5%49 min0.47%B+
Frontier Airlines54277.5%73 min2.03%B

The spread between Delta and Frontier is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.

Route by route

Where Southwest Airlines flies from SMF

Southwest Airlines operates 25 routes out of SMF with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

Southwest Airlines routes from SMF
RouteFlightsOn timeAvg delayCancelledGrade
SMF to SAN · San Diego3,82271.9%49 min0.60%C+
SMF to LAS · Las Vegas3,43078.7%54 min0.29%B+
SMF to BUR · Burbank2,67985.2%52 min1.90%A
SMF to SNA · Santa Ana2,31984.3%43 min0.60%B+
SMF to PHX · Phoenix2,16779.3%52 min0.51%B+
SMF to ONT · Ontario2,11085.0%54 min0.24%A+
SMF to LGB · Long Beach1,91785.7%50 min0.31%A+
SMF to DEN · Denver1,86176.2%50 min0.32%B+
SMF to LAX · Los Angeles1,60578.2%49 min0.19%B+
SMF to PDX · Portland1,20279.3%48 min0.08%B+
SMF to SEA · Seattle1,16978.0%44 min0.17%B+
SMF to BOI · Boise85180.5%45 min0.00%B+
SMF to MDW · Chicago66686.1%35 min0.15%A+
SMF to DAL · Dallas66175.0%48 min0.61%B+
SMF to GEG · Spokane65778.4%50 min0.00%B+
SMF to SLC · Salt Lake City57382.2%57 min0.17%B+
SMF to PSP · Palm Springs50885.3%56 min0.20%A+
SMF to AUS · Austin44679.3%43 min0.22%B+
SMF to SBA · Santa Barbara36687.5%49 min1.09%A
SMF to KOA · Kailua-Kona36589.6%61 min0.00%A+
SMF to EUG · Eugene36583.0%45 min0.00%B+
SMF to HNL · Honolulu36585.8%42 min0.00%A+
SMF to BWI · Baltimorethin sample36483.1%40 min0.82%B+
SMF to HOU · Houstonthin sample36474.1%36 min0.55%C+
SMF to BNA · Nashvillethin sample34689.2%41 min0.29%A+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am5,986 flights93.7%
  • 8am–11am6,555 flights89.5%
  • 11am–2pm5,575 flights78.9%
  • 2pm–5pm5,213 flights70.6%
  • 5pm–8pm4,825 flights69.7%
  • 8pm–5am4,063 flights74.5%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.7% of the time, against 69.7% for the evening window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.

Across the year

Seasonal pattern

On-time rate by calendar month85J84F83M81A78M77J77J83A84S79O80N76D
Darker means more delays. Figures are on-time percentages.January best, December worst

December is the weak month at 76.3% on time, against 85.1% in January. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days.

Delay causes

What holds this operation up

  • Late-arriving aircraft
    56%
  • Carrier
    26%
  • National Airspace System
    17%
  • Extreme weather
    1%
  • Security
    0%

56% 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 305,000 reported delay minutes here, that single category outweighs weather by 56 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.

Cancellations are rare at 0.47%, below the national 1.80% 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.

Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.2% 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.

32,217 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: avoid the 5pm–8pm departure. It runs 69.7% on time against 93.7% for the 5am–8am slot, and that 24 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close.

Common questions

Southwest Airlines at SMF

How often is Southwest Airlines at SMF delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.5% of the 32,217 flights in this analysis, against 22.6% nationally. Delayed flights are late by about 50 minutes on average.

Which airline is most reliable on Southwest Airlines at SMF?

Delta Air Lines leads at 91.2% on time across 3,494 flights. Frontier Airlines is at the other end on 77.5%, a gap of 14 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 Southwest Airlines at SMF?

The 5am–8am departure window is the strongest at 93.7% on time. The 5pm–8pm window is the weakest at 69.7%, 24 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 December delays on Southwest Airlines at SMF?

December is the weakest month at 76.3% on time, compared with 85.1% in January. Across the year that is 9 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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.